A kind of low temperature resistant organic silicon potting glue and preparation method thereof

Abstract

The present invention provides a low-temperature resistant silicone potting adhesive and a preparation method thereof, the preparation method comprising: (1) mixing and degassing the following components to obtain a first mixture: 100 parts of phenyl vinyl silicone oil, 10 to 20 parts of diluent, 10 to 20 parts of curing agent, 2 to 3 parts of tackifier, 0.08 to 0.2 parts of inhibitor; then, mixing and degassing 400 to 500 parts of thermal conductive filler with the first mixture to obtain component A; (2) mixing and degassing the following components to obtain a second mixture: 100 parts of phenyl vinyl silicone oil, 10 to 20 parts of diluent, 0.8 to 1 part of catalyst; then, mixing and degassing 400 to 500 parts of thermal conductive filler with the second mixture to obtain component B. The silicone potting adhesive of the present invention can be cured at room temperature, and has good bonding performance and thermal conductivity, and has high tensile strength, elongation at break, breakdown strength, shear strength, etc.

Description

Technical Field

[0001] The invention relates to the technical field of organosilicon potting adhesives, and in particular to low-temperature resistant organosilicon potting adhesives and a preparation method thereof. Background Art

[0002] With the rapid development of the domestic new energy industry, various power supply technologies have emerged one after another, and their charging efficiency has increased rapidly. At the same time, their internal heat dissipation and protection capabilities have encountered great challenges. For example, some special power supplies need to meet high and low temperature impact tests. In order to meet the above requirements, the circuit board needs to be glued.

[0003] There are three common types of potting glue, namely polyurethane potting glue, epoxy potting glue, and silicone potting glue. Polyurethane potting glue has high strength, but poor flame retardant performance. Epoxy potting glue has excellent adhesion, but too high hardness, easy to produce internal stress, and easy to debond from the bonded substrate under high and low temperature impact environment. Therefore, for the protection of circuit boards, silicone potting glue is mainly used on the market. Silicone potting glue has a large bond energy and good high temperature resistance due to the silicon-oxygen-silicon bond in its main chain structure. At the same time, the methyl group in the side chain makes it have good flexibility. Organic silicon potting glue is divided into two types according to its curing principle, condensation type and addition type. Condensation type potting glue has excellent bonding performance, but it is difficult to improve the thermal conductivity due to moisture curing, which is generally around 0.5wmk. Addition type potting glue can be used to prepare high thermal conductivity potting glue, but the bonding strength is poor. In order to improve the bonding strength, it is often necessary to heat and cure. The use temperature range of the above two types of organic silicon potting glue is generally -50℃~230℃. In the test environment of some special power supplies, it is necessary to meet the use requirements below -55℃. Ordinary organic silicon potting glue will become hard and brittle at this temperature. It is easy to cause the circuit board to debond under high and low temperature impact, and lose the protective effect. Its low temperature resistance needs to be improved. Therefore, how to obtain an organic silicon potting glue that can be cured at room temperature, is resistant to low temperatures, and has good thermal conductivity and bonding properties to meet the protection needs of the above special power supplies is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above problems, the present invention provides a low-temperature resistant organic silicone potting adhesive and a preparation method thereof.

[0005] In one aspect, the present invention provides a method for preparing a low temperature resistant silicone potting adhesive, comprising the following steps:

[0006] (1) Mixing and degassing the following components in parts by mass to obtain a first mixture;

[0007]

[0008] Then, 400 to 500 parts of the thermal conductive filler are mixed with the first mixture and degassed to obtain component A;

[0009] Wherein, the curing agent is selected from phenyl hydrogen-containing silicone oil containing side silicon-hydrogen bonds;

[0010] (2) Mixing and degassing the following components in parts by mass to obtain a second mixture;

[0011] 100 parts of phenyl vinyl silicone oil,

[0012] 10 to 20 parts of diluent,

[0013] Catalyst 0.8-1 part;

[0014] Then, 400 to 500 parts of the thermally conductive filler are mixed with the second mixture and degassed to obtain a B component.

[0015] On the other hand, the present invention also provides a low-temperature resistant silicone potting adhesive, comprising component A and component B;

[0016] In parts by mass, component A comprises:

[0017]

[0018] Wherein, the curing agent is selected from phenyl hydrogen-containing silicone oil containing side silicon-hydrogen bonds;

[0019] In parts by mass, component B comprises:

[0020]

[0021] Optionally, the phenyl vinyl silicone oil is one or more selected from phenyl vinyl silicone oils having a vinyl content of 0.16 to 0.57% and a phenyl content of 2 to 8%.

[0022] Optionally, the curing agent is one or more selected from phenyl hydrogen-containing silicone oils having a side silicon-hydrogen bond content of 0.1 to 0.5% and a phenyl content of 2 to 8%.

[0023] Optionally, the inhibitor is one or more selected from acetylenic alcohols, ether compounds, amine compounds, vinyl ring compounds, and fumarate compounds.

[0024] Optionally, the diluent is one or more selected from α,ω-dimethyl polydimethylphenylsiloxane having a viscosity of 10 to 100 mPa.s and a phenyl content of 2 to 8%.

[0025] Optionally, the structural formula of the tackifier is as follows:

[0026]

[0027] Among them, a≥4, b≥5, c≥4, d≥3, e≥3.

[0028] Optionally, the thermally conductive filler is one or more powders selected from spherical alumina, aluminum hydroxide, and mica of one or several particle sizes.

[0029] Optionally, the particle size of the spherical alumina is 20 to 40 μm, the particle size of the aluminum hydroxide is 10 to 20 μm, and the particle size of the mica is 10 to 20 μm.

[0030] Optionally, the catalyst is a platinum catalyst.

[0031] Beneficial effects:

[0032] (1) The organic silicone potting adhesive of the present invention can be cured at room temperature and has good bonding properties and thermal conductivity, and has high tensile strength, elongation at break, breakdown strength, shear strength, etc.;

[0033] (2) The organic silicone potting adhesive of the present invention has good low temperature resistance and can better withstand high and low temperature impacts. Even when the temperature drops to -70°C, it still has good performance and can meet the protection requirements of special power supplies. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below through examples. Through these examples, the features and advantages of the present invention will become clearer and more specific.

[0035] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0036] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0037] In one aspect, the present invention provides a method for preparing a low temperature resistant silicone potting adhesive, comprising the following steps:

[0038] (1) Mixing and degassing the following components in parts by mass to obtain a first mixture;

[0039]

[0040] Then, 400 to 500 parts of the thermal conductive filler are mixed with the first mixture and degassed to obtain component A;

[0041] Wherein, the curing agent is selected from phenyl hydrogen-containing silicone oil containing side silicon-hydrogen bonds;

[0042] (2) Mixing and degassing the following components in parts by mass to obtain a second mixture;

[0043] 100 parts of phenyl vinyl silicone oil,

[0044] 10 to 20 parts of diluent,

[0045] Catalyst 0.8-1 part;

[0046] Then, 400 to 500 parts of the thermally conductive filler are mixed with the second mixture and degassed to obtain a B component.

[0047] It should be noted that the preparation method of the low-temperature resistant silicone potting glue of the present invention has the advantages of being simple and easy to implement. In step (1), phenyl vinyl silicone oil, diluent, curing agent, tackifier, and inhibitor are first mixed and degassed according to the above-mentioned mass parts, and then mixed and degassed with a thermally conductive filler to obtain component A; in step (2), phenyl vinyl silicone oil, diluent, and catalyst are first mixed and degassed according to the above-mentioned mass parts, and then mixed and degassed with a thermally conductive filler to obtain component B; when in use, component A and component B can be mixed in a mass ratio of 1:1, and after curing at room temperature, the low-temperature resistant silicone potting glue is obtained, which is easy to use.

[0048] The present invention uses the above components and compound them according to the above mass parts to prepare component A and component B respectively, especially using phenyl hydrogen silicone oil with side silicon-hydrogen bonds as a curing agent and compounding it with phenyl vinyl silicone oil, a diluent, a tackifier, an inhibitor, and a thermally conductive filler to prepare component A, and using phenyl vinyl silicone oil, a diluent, a catalyst, and a thermally conductive filler to prepare component B. At this time, the phenyl hydrogen-containing silicone oil with side silicon-hydrogen bonds can not only play a good curing role, but the presence of the phenyl hydrogen-containing silicone oil with side silicon-hydrogen bonds forms a synergistic system between the aforementioned multiple components in the silicone potting adhesive. The silicone potting adhesive can be well cured at room temperature such as 20-30°C, and has good bonding and thermal conductivity. It performs well in the tests of performance parameters such as tensile strength, elongation at break, breakdown strength, and shear strength. In addition, the silicone potting adhesive has good low temperature resistance, high and low temperature impact resistance, flame retardant properties, and voltage resistance. It still has good performance at a low temperature of -70°C, and can well meet the protection needs of special power supplies. It can be used for thermal conductive potting and bonding of circuit boards in many fields such as special power supplies, electronics, and military industry.

[0049] On the other hand, the present invention also provides a low-temperature resistant silicone potting adhesive, comprising component A and component B;

[0050] In parts by mass, component A comprises:

[0051]

[0052] Wherein, the curing agent is selected from phenyl hydrogen-containing silicone oil containing side silicon-hydrogen bonds;

[0053] In parts by mass, component B comprises:

[0054]

[0055] It should be noted that silicone oil usually refers to linear polysiloxane products that remain in liquid state at room temperature, which are generally divided into two categories: methyl silicone oil and modified silicone oil. The most commonly used silicone oil is methyl silicone oil, also known as ordinary silicone oil, whose organic groups are all methyl, and its structure can be shown as follows: Methyl silicone oil has good chemical stability, insulation, and good hydrophobic properties. Phenyl vinyl silicone oil refers to silicone oil containing phenyl and vinyl. Phenyl hydrogen silicone oil refers to silicone oil containing phenyl and silicon-hydrogen bonds. Phenyl hydrogen silicone oil with silicon-hydrogen bonds on the side can refer to phenyl hydrogen silicone oil with silicon-hydrogen bonds on the side. Phenyl hydrogen silicone oil with silicon-hydrogen bonds on the side can be schematically shown but not limited to the following structure:

[0056]

[0057] Two-component glue may include two independent components, such as component A and component B. Component A and component B may be made of many specific components respectively, and component A and component B need to be mixed before use. When the silicone potting glue of the present invention is used, component A and component B in a mass ratio of 1:1 can be mixed first, and silicone potting glue with excellent performance can be obtained by curing at room temperature. It has been found that if the components with the same ratio relationship as mentioned above are used in a single-component form, premature contact between the components greatly reduces the performance of the silicone potting glue. The two-component form of AB components makes the silicone potting glue have excellent comprehensive performance. In particular, phenyl hydrogenated silicone oil with side silicon-hydrogen bonds is used as a curing agent, and is compounded with phenyl vinyl silicone oil, diluent, tackifier, inhibitor, and thermal conductive filler to obtain component A, and phenyl vinyl silicone oil, diluent, catalyst, and thermal conductive filler are compounded to obtain component B. At this time, the phenyl hydrogen-containing silicone oil with side silicon-hydrogen bonds can not only play a good curing role, but the presence of the phenyl hydrogen-containing silicone oil with side silicon-hydrogen bonds forms a synergistic enhancement system between the aforementioned multiple components in the silicone potting adhesive. The silicone potting adhesive can be well cured at room temperature such as 20-30°C, and has good bonding and thermal conductivity. It performs well in the tests of performance parameters such as tensile strength, elongation at break, breakdown strength, and shear strength. In addition, the silicone potting adhesive has good low temperature resistance, high and low temperature impact resistance, flame retardant properties, and voltage resistance. It still has good performance at a low temperature of -70°C, and can well meet the protection needs of special power supplies.

[0058] In one embodiment of the aforementioned low-temperature resistant silicone potting adhesive of the present invention, the phenyl vinyl silicone oil is one or more selected from phenyl vinyl silicone oils having a vinyl content of 0.16 to 0.57% and a phenyl content of 2 to 8%.

[0059] It should be noted that, in the low-temperature resistant silicone potting compound of the present invention, the phenyl vinyl silicone oil in component A and component B may be the same or different, and may be selected from one or more phenyl vinyl silicone oils having a vinyl content of 0.16 to 0.57% and a phenyl content of 2 to 8%. Compounding such phenyl vinyl silicone oil with other components to form component A and component B, respectively, is conducive to obtaining a silicone potting compound with excellent comprehensive performance.

[0060] Alternatively, phenyl vinyl silicone oil can be synthesized as follows:

[0061] Take 15-64g of octaphenylcyclotetrasiloxane D4 Ph , 200-340g octamethylcyclotetrasiloxane D4, 4-20g tetramethyldivinylsiloxane, add 10-20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually raise the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer.

[0062] In another embodiment of the aforementioned low temperature resistant silicone potting adhesive of the present invention, the curing agent is one or more selected from phenyl hydrogen-containing silicone oils having a side silicon hydrogen bond content of 0.1 to 0.5% and a phenyl content of 2 to 8%.

[0063] It should be noted that because the curing agent is a phenyl hydrogen-containing silicone oil containing side silicon-hydrogen bonds, the side silicon-hydrogen bond content is the silicon-hydrogen bond content. Using one or more phenyl hydrogen-containing silicone oils with a side silicon-hydrogen bond content of 0.1-0.5% and a phenyl content of 2-8% as the curing agent, such a curing agent can not only better exert the curing effect, but also is conducive to better synergistic enhancement between multiple components. The silicone potting adhesive can better complete curing at room temperature, and various properties such as bonding performance, thermal conductivity, and low temperature resistance are further improved.

[0064] In addition, the aforementioned phenyl hydrogen silicone oil as a curing agent can be synthesized as follows:

[0065] Take 15-64g of octaphenylcyclotetrasiloxane D4 Ph , 200-340g octamethylcyclotetrasiloxane D4, 30-50g tetramethylhydrogencyclotetrasiloxane D4 H , 3-9g hexamethyldisiloxane, add 10-20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually raise the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer.

[0066] In another embodiment of the aforementioned low-temperature resistant silicone potting adhesive of the present invention, the inhibitor is one or more selected from acetylenic alcohols, ether compounds, amine compounds, vinyl ring compounds, and maleic ester compounds.

[0067] It should be noted that the above-mentioned type of inhibitor is compounded with phenyl vinyl silicone oil, diluent and other components to form component A, so that an organosilicon potting adhesive with excellent performance can be obtained.

[0068] In one embodiment of the aforementioned low temperature resistant silicone potting adhesive of the present invention, the diluent is one or more selected from α,ω-dimethyl polydimethylphenylsiloxane having a viscosity of 10 to 100 mPa.s and a phenyl content of 2 to 8%.

[0069] It should be noted that the diluents in component A and component B may be the same or different. The diluents in component A and component B may be selected from α, ω-dimethyl polydimethylphenylsiloxane with a viscosity of 10 to 100 mPa.s and a phenyl content of 2 to 8%. When such a diluent is compounded with other components, the resulting silicone potting compound has excellent properties.

[0070] In addition, the aforementioned diluent can be synthesized as follows:

[0071] Take 15-64g of octaphenylcyclotetrasiloxane D4 Ph , 200-340g octamethylcyclotetrasiloxane D4, 30-50g tetramethylcyclotetrasiloxane D 4 , 3-9g hexamethyldisiloxane, add 10-20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually raise the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer.

[0072] In another embodiment of the aforementioned low temperature resistant silicone potting adhesive of the present invention, the structural formula of the tackifier is as follows:

[0073]

[0074] Among them, a≥4, b≥5, c≥4, d≥3, e≥3.

[0075] After years of research and development experiments, the inventors of the present application unexpectedly discovered that by using polydimethylphenylsiloxane containing phenyl, acyloxy, epoxy and silicon-hydrogen bonds and having the structure shown above as a tackifier, and compounding it with the above-mentioned phenyl vinyl silicone oil, diluent, curing agent and other components to form component A, and compounding the above-mentioned components to form component B, the various properties of the silicone potting compound such as low temperature resistance and high and low temperature impact resistance are further greatly improved, and it can be better cured at room temperature of 20 to 30°C, and the bonding performance, thermal conductivity, tensile strength, elongation at break, breakdown strength, shear strength, etc. are further greatly improved, so as to obtain a high-quality silicone potting compound with greatly improved comprehensive performance.

[0076] In addition, the aforementioned tackifier can be synthesized as follows:

[0077] Take 30-50g of octaphenylcyclotetrasiloxane D4 Ph , 160-185g octamethylcyclotetrasiloxane D4, 22-34g tetramethylhydrogencyclotetrasiloxane D4 H , 3-7g hexamethyldisiloxane, add 15-25g of 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for a certain time, distill under reduced pressure and gradually raise the temperature to 200-250°C, and stop the reaction when there is no distillate. Take 150-180g of the transparent polymer in the bottle, put it in a 500ml three-necked flask, add 300-350ml of toluene solvent, add 3-4g of 1000-3000ppm isopropanol solution of chloroplatinic acid, control the reaction temperature between 30-60°C through an oil bath, add 40-45g of 3-(methacryloyloxy)propyltrimethoxysilane drop by drop, and continue to add 36-42g of allyl glycidyl ether drop by drop after adding, maintain the above temperature, react for a certain time, distill the product after the reaction is completed, remove the low-boiling substances, and obtain the above transparent tackifier.

[0078] In one embodiment of the aforementioned low-temperature resistant silicone potting adhesive of the present invention, the thermally conductive filler is one or more powders selected from spherical alumina, aluminum hydroxide, and mica of one or several particle sizes.

[0079] It should be noted that the thermally conductive fillers in component A and component B may be the same or different, and the thermally conductive fillers in component A and component B are each selected from one or more powders of spherical alumina, aluminum hydroxide, and mica of one or several particle sizes.

[0080] In one embodiment of the aforementioned low-temperature resistant silicone potting adhesive of the present invention, the particle size of spherical alumina is 20-40 μm, the particle size of aluminum hydroxide is 10-20 μm, and the particle size of mica is 10-20 μm.

[0081] It should be noted that, by compounding the thermal conductive filler with the above-mentioned particle size with other components, an organosilicon potting compound with excellent performance can be obtained.

[0082] In one embodiment of the aforementioned low-temperature resistant silicone potting adhesive of the present invention, the catalyst is a platinum catalyst.

[0083] It should be noted that the organic silicone potting compound obtained by compounding the platinum catalyst with other components exhibits excellent performance in the aforementioned aspects.

[0084] The present invention is further described in detail by way of examples below, but the present invention is not limited thereto. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0085] Example 1

[0086] The mass fractions of component A are as follows:

[0087]

[0088] The mass fractions of component B are as follows:

[0089]

[0090] In this example, the following are used:

[0091] The vinyl content of phenyl vinyl silicone oil is 0.16%, and the phenyl content is 2%. The synthesis process is as follows:

[0092] Take 15g of octaphenylcyclotetrasiloxane D4 Ph , 340g octamethylcyclotetrasiloxane D4, 10g tetramethyldivinylsiloxane, add 10g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually increase the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0093] The curing agent is phenyl hydrogen silicone oil with side silicon-hydrogen bonds, with a side silicon-hydrogen bond content of 0.5% and a phenyl content of 2%. The synthesis process is as follows:

[0094] Take 64g of octaphenylcyclotetrasiloxane D4 Ph , 340g octamethylcyclotetrasiloxane D4, 40g tetramethylhydrogencyclotetrasiloxane D4 H , 9g hexamethyldisiloxane, add 20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually increase the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0095] The inhibitor was tetramethyltetravinylcyclotetrasiloxane;

[0096] The diluent is α,ω-dimethyl polydimethylphenylsiloxane with a viscosity of 100mpa.s and a phenyl content of 5%. The synthesis method is as follows:

[0097] Take 15g of octaphenylcyclotetrasiloxane D4 Ph , 340g octamethylcyclotetrasiloxane, 30g tetramethylcyclotetrasiloxane, 3g hexamethyldisiloxane, add 10g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually raise the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0098] The structure of the tackifier is:

[0099]

[0100] Among them, a≥4, b≥5, c≥4, d≥3, e≥3;

[0101] The preparation method of the above structural tackifier is as follows:

[0102] Take 30g of octaphenylcyclotetrasiloxane D4 Ph , 160g octamethylcyclotetrasiloxane D4, 22g tetramethylhydrogencyclotetrasiloxane D4 H , 3g hexamethyldisiloxane, add 15g of 98% concentrated sulfuric acid, control the reaction temperature at 30-50℃, react for 24h, distill under reduced pressure and gradually heat to 230℃, and stop the reaction when there is no distillate. Take 150g of the transparent polymer in the bottle, put it in a 500ml three-necked flask, add 300ml of toluene solvent, add 3g of 2000ppm isopropanol solution of chloroplatinic acid, control the reaction temperature between 30 and 60℃ by oil bath, add 40g of 3-(methacryloyloxy)propyltrimethoxysilane drop by drop, and continue to add 36g of allyl glycidyl ether drop by drop after adding, maintain the above temperature, react for 4h, distill the product after the reaction, remove the low boiling point, and obtain the above transparent tackifier. After nuclear magnetic hydrogen spectrum and carbon spectrum test, it is known that the structural formula of the prepared tackifier is the above formula.

[0103] The filler is 300 parts of spherical alumina with a particle size of 20 μm, 50 parts of aluminum hydroxide with a particle size of 10 μm, and 50 parts of mica with a particle size of 10 μm;

[0104] The catalyst is chloroplatinic acid.

[0105] The preparation method of this potting glue is as follows:

[0106] a) weighing phenyl vinyl silicone oil, diluent, curing agent, inhibitor and tackifier in parts by mass, adding them into a blender, mixing and degassing for 5 min at a vacuum degree of -0.9 MPa and a rotation speed of 1000 r / min to obtain a mixture;

[0107] b) adding fillers according to mass parts to the above mixture, and then mixing and degassing in a mixer at a speed of 1500 r / min and a vacuum degree of -0.9 MPa for 10 min to obtain component A;

[0108] c) weighing phenyl vinyl silicone oil, catalyst, and diluent in parts by mass, adding them into a blender, mixing and degassing at a speed of 1000 r / min and a vacuum degree of -0.9 MPa for 5 min to obtain a mixture;

[0109] d) The filler was weighed by weight and added to the above mixture, and then mixed and degassed in a mixer at a speed of 1500 r / min and a vacuum degree of -0.9 MPa for 10 min to obtain component B.

[0110] Example 2

[0111] The mass fractions of component A are as follows:

[0112]

[0113] The mass fractions of component B are as follows:

[0114]

[0115] In this example, the following are used:

[0116] The vinyl content of phenyl vinyl silicone oil is 0.57%, the phenyl content is 8%, and the synthesis method is as follows:

[0117] Take 64g of octaphenylcyclotetrasiloxane D4 Ph , 240g octamethylcyclotetrasiloxane D4, 16g tetramethyldivinylsiloxane, add 20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually increase the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0118] The curing agent is phenyl hydrogen silicone oil with side silicon-hydrogen bonds, the side silicon-hydrogen bond content is 0.1%, and the phenyl content is 8%. The synthesis method is as follows:

[0119] Take 64g of octaphenylcyclotetrasiloxane D4 Ph , 200g octamethylcyclotetrasiloxane D4, 35g tetramethylhydrogencyclotetrasiloxane D4 H , 3g hexamethyldisiloxane, add 20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually increase the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0120] The inhibitor is acetylene alcohol;

[0121] The diluent is α,ω-dimethyl polydimethylphenylsiloxane with a viscosity of 10mpa.s and a phenyl content of 8%. The synthesis method is as follows:

[0122] Take 64g of octaphenylcyclotetrasiloxane D4 Ph , 280g octamethylcyclotetrasiloxane, 36g tetramethylcyclotetrasiloxane, 5g hexamethyldisiloxane, add 12g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually raise the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0123] The tackifier is the same as in Example 1;

[0124] The filler is 400 parts of spherical alumina with a particle size of 20 μm, 50 parts of aluminum hydroxide with a particle size of 10 μm, and 50 parts of mica with a particle size of 10 μm;

[0125] The catalyst is the same as in Example 1;

[0126] The preparation method of the organosilicon potting adhesive is the same as that of Example 1.

[0127] Example 3

[0128] The mass fractions of component A are as follows:

[0129]

[0130] The mass fractions of component B are as follows:

[0131]

[0132] In this example, the following are used:

[0133] The vinyl content of phenyl vinyl silicone oil is 0.53%, the phenyl content is 6%, and the synthesis method is as follows:

[0134] Take 52g of octaphenylcyclotetrasiloxane D4 Ph , 340g octamethylcyclotetrasiloxane D4, 15g tetramethyldivinylsiloxane, add 10g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually increase the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0135] The curing agent is phenyl hydrogen silicone oil with side silicon-hydrogen bonds, the side silicon-hydrogen bond content is 0.5%, and the phenyl content is 6%. The synthesis method is as follows:

[0136] Take 55g of octaphenylcyclotetrasiloxane D4 Ph , 230g octamethylcyclotetrasiloxane D4, 48g tetramethylhydrogencyclotetrasiloxane D4 H , 9g hexamethyldisiloxane, add 20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually increase the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0137] The inhibitor was dibutyl fumarate;

[0138] The diluent is α,ω-dimethyl polydimethylphenylsiloxane with a viscosity of 50mpa.s and a phenyl content of 5%. The synthesis method is as follows:

[0139] Take 18g of octaphenylcyclotetrasiloxane D4 Ph , 330g octamethylcyclotetrasiloxane, 50g tetramethylcyclotetrasiloxane, 9g hexamethyldisiloxane, add 20g 98% concentrated sulfuric acid, control the reaction temperature at 30-50°C, react for 24h, distill under reduced pressure and gradually raise the temperature to 230°C, stop the reaction when there is no distillate, and obtain a transparent polymer;

[0140] The tackifier is the same as in Example 1;

[0141] The filler is 300 parts of spherical alumina with a particle size of 20 μm, 50 parts of aluminum hydroxide with a particle size of 10 μm, and 100 parts of mica with a particle size of 10 μm;

[0142] The catalyst is the same as in Example 1;

[0143] The preparation method of the organosilicon potting adhesive is the same as that of Example 1.

[0144] Comparative Example 1

[0145] The silicone potting compound was prepared according to the formula and method of Example 1, except that:

[0146] Replace the tackifier with the following structural tackifier:

[0147]

[0148] x≥8, y≥5, and z≥4; the preparation method of the tackifier is as follows:

[0149] Take 24g of tetramethylhydrogencyclotetrasiloxane D 4 H, 16.3g of vinyltrimethoxysilane and 13.7g of allyl glycidyl ether were placed in a 250mL three-necked flask, 30mL of toluene was added as a solvent, and the reaction was carried out under nitrogen protection at a reaction temperature of 80°C for 4 hours; after the reaction was completed, the product was distilled to remove low-boiling substances to obtain a transparent tackifier.

[0150] Test Case

[0151] In order to investigate the mechanical properties and thermal conductivity of the silicone potting glue in the aforementioned embodiments and comparative examples, the components A and B of the silicone potting glue in the aforementioned embodiments and comparative examples were mixed at a mass ratio of 1:1 at 23°C, vacuum degassed, and cured for 24 hours to prepare a 2 mm thick test piece, and a tensile performance test was performed. The bonding test was performed according to the shear standard. The curing conditions were the same as above. The relevant test results are shown in Table 1 below.

[0152] Among them, the thermal conductivity is tested according to GB10294-2008;

[0153] Hardness is tested according to GB / T 531.1-2008;

[0154] The tensile strength is tested according to GB / T 528-2009;

[0155] Elongation at break is tested according to GB / T 528-2009;

[0156] The breakdown strength is tested according to GB / T 1695-2005;

[0157] Shear strength is tested according to GB / T 7124-2008;

[0158] The low-temperature hardening temperature is measured by DSC (differential scanning calorimetry).

[0159] Table 1. Mechanical properties and thermal conductivity test results:

[0160]

[0161]

[0162] It can be seen from the test results in Table 1 that the silicone potting glue of the embodiment of the present invention can be well cured at room temperature, and has good mechanical properties, thermal conductivity, etc. The silicone potting glue of the present invention has very good low temperature resistance and can still maintain good elasticity and other properties at a temperature as low as -70°C; in Comparative Example 1, the tackifier is replaced with other tackifiers, resulting in a decrease in the tensile strength, elongation at break, shear strength and other properties of the silicone potting glue. It can be seen that the present invention significantly improves the comprehensive performance of the silicone potting glue by using the tackifier with the aforementioned specific structure.

[0163] In the description of the present application, it should be noted that the terms "upper", "lower", "inside", "outside", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships in the working state of the present application. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present application.

[0164] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect" and "connect" should be understood in a broad sense. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0165] The present application has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, various replacements and improvements can be made to the present application, all of which fall within the scope of protection of the present application.

Claims

1. A method for preparing a low temperature resistant silicone potting adhesive, characterized in that: The steps include: (1) Mixing and degassing the following components in parts by mass to obtain a first mixture; Then, 400 to 500 parts of the thermal conductive filler are mixed with the first mixture for degassing to obtain component A; wherein the curing agent is selected from phenyl hydrogen-containing silicone oil containing side silicon-hydrogen bonds; (2) Mixing and degassing the following components in parts by mass to obtain a second mixture; 100 parts of phenyl vinyl silicone oil, 10 to 20 parts of diluent, Catalyst 0.8-1 part; Then, 400 to 500 parts of the thermally conductive filler are mixed with the second mixture and degassed to obtain a B component.

2. A low temperature resistant silicone potting adhesive, characterized in that: It contains component A and component B; In parts by mass, component A comprises: Wherein, the curing agent is selected from phenyl hydrogen-containing silicone oil containing side silicon-hydrogen bonds; In parts by mass, component B comprises:

3. The low temperature resistant silicone potting adhesive according to claim 2, characterized in that: The phenyl vinyl silicone oil is one or more selected from phenyl vinyl silicone oils having a vinyl content of 0.16 to 0.57% and a phenyl content of 2 to 8%.

4. The low temperature resistant silicone potting adhesive according to claim 2, characterized in that: The curing agent is one or more selected from phenyl hydrogen-containing silicone oils having a side silicon-hydrogen bond content of 0.1 to 0.5% and a phenyl content of 2 to 8%.

5. The low temperature resistant silicone potting adhesive according to claim 2, characterized in that: The inhibitor is one or more selected from acetylenic alcohols, ether compounds, amine compounds, vinyl ring compounds, and fumarate compounds.

6. The low temperature resistant silicone potting adhesive according to claim 2, characterized in that: The diluent is one or more selected from α,ω-dimethyl polydimethylphenylsiloxane with a viscosity of 10 to 100 mPa.s and a phenyl content of 2 to 8%.

7. The low temperature resistant silicone potting adhesive according to claim 2, characterized in that: The structural formula of the tackifier is shown below: Among them, a≥4, b≥5, c≥4, d≥3, e≥3.

8. The low temperature resistant silicone potting adhesive according to claim 2, characterized in that: The thermal conductive filler is one or more powders selected from spherical aluminum oxide, aluminum hydroxide, and mica with one or several particle sizes.

9. The low temperature resistant silicone potting adhesive according to claim 8, characterized in that: The particle size of spherical alumina is 20 to 40 μm, the particle size of aluminum hydroxide is 10 to 20 μm, and the particle size of mica is 10 to 20 μm.

10. The low temperature resistant silicone potting adhesive according to claim 2, characterized in that: The catalyst is a platinum catalyst.

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