Heat-resistant pouring sealant as well as preparation method and application thereof

Abstract

The invention discloses a heat-resistant pouring sealant as well as a preparation method and application thereof, and belongs to the technical field of pouring sealants. Comprising the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane, 18-25 parts of a plasticizer, 14-20 parts of modified talcum powder, 2-5 parts of fumed silica, 1-3 parts of silica powder, 6-10 parts of potassium 3-(phenylsulfonyl) benzenesulfonate, 2-5 parts of a cross-linking agent, 2-4 parts of a coupling agent and 0.2-0.5 part of a catalyst, the plasticizer comprises vinyl silicone oil and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil to the cashew nut shell oil phenolic resin is (3-5): 1. The pouring sealant provided by the invention has excellent heat resistance and bonding strength.

Description

Technical Field

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

[0002] Potting compounds are widely used in electronic components, devices, power equipment and other fields. Their main function is to provide mechanical protection, insulation, moisture resistance and heat resistance for electronic components. With the development of modern industry, the performance requirements for potting compounds are getting higher and higher. Especially in some high temperature environments, traditional potting compounds often cannot meet the use requirements. Therefore, it is particularly important to develop a potting compound with excellent heat resistance.

[0003] Existing potting compounds, such as silicone potting compounds, epoxy resin potting compounds and polyurethane potting compounds, although they have excellent insulation and mechanical protection properties, often have unstable performance in high temperature environments and cannot take into account bonding strength.

[0004] In view of this, this application is filed. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a heat-resistant potting adhesive and a preparation method and application thereof, which have excellent heat resistance and bonding strength.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane, 18 to 25 parts of a plasticizer, 14 to 20 parts of modified talc, 2 to 5 parts of fumed silica, 1 to 3 parts of silicon powder, 6 to 10 parts of potassium 3-phenylsulfonylbenzenesulfonate, 2 to 5 parts of a crosslinking agent, 2 to 4 parts of a coupling agent, and 0.2 to 0.5 parts of a catalyst;

[0008] The plasticizer comprises vinyl silicone oil and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil to the cashew nut shell oil phenolic resin is (3-5):1.

[0009] As a preferred embodiment of the present invention, the viscosity of the alkoxy-terminated polydimethylsiloxane at 25° C. is 20,000 to 35,000 mPa·s.

[0010] As a preferred embodiment of the present invention, the viscosity of the vinyl silicone oil at 25° C. is 1000 to 5000 mPa·s, and the vinyl content of the vinyl silicone oil is 0.18 to 0.3 wt %.

[0011] As a preferred embodiment of the present invention, the cashew nut shell oil phenolic resin has a viscosity of 800 to 1300 mPa·s at 25° C. and a hydroxyl value of 173 to 193 mgKOH / g.

[0012] As a preferred embodiment of the present invention, the preparation method of the modified talc is:

[0013] (1) treating talc powder with plasma to obtain pretreated talc powder;

[0014] (2) adding pretreated talcum powder and citric acid to a sulfuric acid solution, stirring evenly, and then adding γ-glycidyloxypropyltrimethoxysilane, stirring evenly, to obtain a precursor solution;

[0015] (3) adding 4-vinylbenzeneboronic acid, boric acid and azobisisobutyronitrile to hydroxyl-terminated polydimethylsiloxane, reacting at 80-95° C. for 2-6 hours to obtain a modified solution;

[0016] (4) Add the modified liquid to the precursor liquid, stir evenly at 65-80° C., ultrasonically treat, filter, and dry to obtain modified talc.

[0017] As a preferred embodiment of the present invention, the voltage of the plasma treatment is 220V, the power is 600-800W, and the time is 2-5min.

[0018] As a preferred embodiment of the present invention, the mass ratio of the pretreated talc, citric acid, sulfuric acid solution and γ-glycidyloxypropyltrimethoxysilane is 1:(0.05-0.2):(2-5):(0.02-0.08).

[0019] As a preferred embodiment of the present invention, the mass ratio of 4-vinylbenzeneboronic acid, boric acid, azobisisobutyronitrile, and hydroxyl-terminated polydimethylsiloxane is (0.1-0.2): (0.1-0.2): (0.02-0.05): 1;

[0020] The mass ratio of the modifying liquid to the precursor liquid is 1:(8-12).

[0021] As a preferred embodiment of the present invention, the crosslinking agent includes at least one of methyl tributylacetoximate silane, phenyl tributylacetoximate silane, and methyl vinyl dibutyl ketone oxime silane;

[0022] The catalyst includes at least one of dibutyltin dilaurate, dibutyltin diacetate, and stannous octoate;

[0023] The coupling agent includes at least one of 3-isocyanate propyl triethoxy silane and γ-isocyanate propyl trimethoxy silane.

[0024] The present invention also provides a method for preparing a heat-resistant potting adhesive, comprising the following steps:

[0025] The alkoxy-terminated polydimethylsiloxane, the plasticizer and the cross-linking agent are mixed evenly, and then the modified talcum powder, the fumed silica and the silicon micropowder are added and mixed evenly, and finally the coupling agent and the catalyst are added and mixed evenly to obtain the heat-resistant potting adhesive.

[0026] The invention also provides an application of the heat-resistant potting adhesive in electronic components and optical devices.

[0027] The beneficial effects of the present invention are as follows: (1) the vinyl silicone oil of the present invention has excellent heat resistance, flexibility and adhesion. The vinyl group in the vinyl silicone oil can participate in the reaction, which can increase the crosslinking density of the potting compound and enhance its network structure. At the same time, the flexibility and active vinyl functional group of the vinyl silicone oil can form a good interface with other organic components or fillers (such as modified talcum powder, silica powder and gas silica), which helps to enhance the bonding strength of the potting compound; the cashew nut shell oil phenolic resin has excellent heat resistance, chemical resistance and good bonding performance, and the cashew nut shell oil phenolic resin can give the material higher thermal stability. (2) The phenolic in the cashew nut shell oil phenolic resin has excellent high temperature resistance and can resist thermal decomposition. The chain structure of cashew nut shell oil makes it have good oxidation resistance and heat resistance at high temperature, the aromatic group of phenolic resin not only provides excellent thermal stability, but also can reduce the thermal motion of polymer molecules at high temperature, thereby improving the heat resistance of potting glue, and cashew nut shell oil phenolic resin has strong polarity, which can enhance the adsorption of materials and various surfaces; the present invention uses vinyl silicone oil and cashew nut shell oil phenolic resin together, and the vinyl group in the vinyl silicone oil can cross-link with the hydroxyl or other reactive groups in the cashew nut shell oil phenolic resin to form a more compact and stable network structure. Since cashew nut shell oil phenolic resin itself has strong heat resistance, combined with the high temperature cross-linking performance of vinyl silicone oil, the two can jointly improve the heat resistance and thermal stability of the material in the potting glue; the flexibility of vinyl silicone oil is combined with the high rigidity of cashew nut shell oil phenolic resin to form a cross-linked structure with both flexibility and strength, so that the potting glue can maintain structural integrity at high temperature and delay thermal aging. Vinyl silicone oil can provide a good bonding interface, while the polarity and hydroxyl groups of cashew nut shell oil phenolic resin can enhance its chemical and physical bonding with the substrate. The two work synergistically to improve the bonding strength of the potting compound. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0029] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0030] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0031] In the present application, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0032] Unless otherwise specified, the components, raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the components and raw materials used in each parallel experiment are all of the same kind.

[0033] The raw materials used in the examples and comparative examples are described as follows:

[0034] Alkoxy-terminated polydimethylsiloxane-1: viscosity at 25°C is 20000 mPa·s, Jiangxi Kexing New Materials, brand J-200.

[0035] Alkoxy-terminated polydimethylsiloxane-2: viscosity at 25°C is 35000 mPa·s, Jiangxi Kexing New Materials, brand F-40A.

[0036] Alkoxy-terminated polydimethylsiloxane-3: viscosity at 25°C is 10000 mPa·s, Jiangxi Kexing New Materials, brand F-10A.

[0037] Alkoxy-terminated polydimethylsiloxane-4: viscosity at 25°C is 80,000 mPa·s, Jiangxi Kexing New Materials, brand J-800.

[0038] Vinyl silicone oil-1: viscosity at 25°C is 5000 mPa·s, vinyl content is 0.18 wt%, Jiangxi Kexing New Materials, brand V-5000.

[0039] Vinyl silicone oil-2: viscosity at 25°C is 1000 mPa·s, vinyl content is 0.3 wt%, Jiangxi Kexing New Materials, brand V-1000.

[0040] Vinyl silicone oil-3: viscosity at 25°C is 500 mPa·s, vinyl content is 0.43 wt%, Jiangxi Kexing New Materials, brand V-500.

[0041] Vinyl silicone oil-4: viscosity at 25°C is 10000 mPa·s, vinyl content is 0.12 wt%, Jiangxi Kexing New Materials, brand V-10000.

[0042] Cashew nut shell oil phenolic resin: viscosity at 25°C is 800-1300 mPa·s, hydroxyl value is 173-193 mgKOH / g, Cardolite, NX4005.

[0043] Filler: Fumed silica, specific surface area 180m 2 / g, commonly available in the market.

[0044] Silica powder: 800 mesh, Guangzhou Haiqi New Materials.

[0045] Hydroxyl terminated polydimethylsiloxane: McLean reagent, brand 768075.

[0046] Talc: Heshan Chemical, brand A50.

[0047] Crosslinking agent: methyl tributylidene silane.

[0048] Catalyst: dibutyltin dilaurate.

[0049] Coupling agent: γ-glycidyloxypropyltrimethoxysilane.

[0050] The embodiment of the present application provides a heat-resistant potting adhesive, comprising the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane, 18 to 25 parts of plasticizer, 14 to 20 parts of modified talc, 2 to 5 parts of fumed silica, 1 to 3 parts of silicon powder, 6 to 10 parts of potassium 3-phenylsulfonylbenzenesulfonate, 2 to 5 parts of cross-linking agent, 2 to 4 parts of coupling agent, and 0.2 to 0.5 parts of catalyst;

[0051] The plasticizer comprises vinyl silicone oil and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil to the cashew nut shell oil phenolic resin is (3-5):1.

[0052] The present invention creatively combines the above-mentioned raw materials to obtain a potting compound with excellent heat resistance and bonding strength, wherein the vinyl silicone oil has excellent heat resistance, flexibility and adhesion, the vinyl group in the vinyl silicone oil can participate in the reaction, can improve the crosslinking density of the potting compound, and enhance its network structure, while the flexibility and active vinyl functional group of the vinyl silicone oil can form a good interface with other organic components or fillers (such as modified talcum powder, silicon powder and gas silicon), which helps to enhance the bonding strength of the potting compound; the cashew nut shell oil phenolic resin has excellent heat resistance, chemical resistance and good bonding performance, and the cashew nut shell oil phenolic resin can give the material higher thermal stability.

[0053] Among them, the phenolic in cashew shell oil phenolic resin has excellent high temperature resistance and can resist thermal decomposition. The chain structure of cashew shell oil makes it have good oxidation resistance and heat resistance at high temperature, and the aromatic group of phenolic resin not only provides excellent thermal stability, but also can reduce the thermal motion of polymer molecules at high temperature, thereby improving the heat resistance of potting glue, and cashew shell oil phenolic resin has strong polarity, which can enhance the adsorption of materials and various surfaces; the present invention combines vinyl silicone oil and cashew shell oil phenolic resin, and the vinyl group in vinyl silicone oil can cross-link with the hydroxyl or other reactive groups in cashew shell oil phenolic resin to form a more compact and stable network structure. Because cashew shell oil phenolic resin itself has strong heat resistance, combined with the high temperature cross-linking performance of vinyl silicone oil, the two can jointly improve the heat resistance and thermal stability of materials in potting glue; the flexibility of vinyl silicone oil is combined with the high rigidity of cashew shell oil phenolic resin to form a cross-linked structure with both flexibility and strength, so that the potting glue can maintain structural integrity at high temperature and delay thermal aging. Vinyl silicone oil can provide a good bonding interface, while the polarity and hydroxyl groups of cashew nut shell oil phenolic resin can enhance its chemical and physical bonding with the substrate. The two work synergistically to improve the bonding strength of the potting compound.

[0054] In one embodiment, the viscosity of the alkoxy-terminated polydimethylsiloxane at 25°C is 20,000 to 35,000 mPa·s. When the viscosity is within this range, the compatibility of the raw materials in the formula is good, which can promote the formation of a denser cross-linked network structure, while promoting the uniform dispersion of other ingredients in the system, improving fluidity and processing performance, thereby further improving the bonding strength.

[0055] In one embodiment, the viscosity of the vinyl silicone oil at 25° C. is 1000 to 5000 mPa·s, and the vinyl content of the vinyl silicone oil is 0.18 to 0.3 wt %.

[0056] In one embodiment, the cashew nut shell oil phenolic resin has a viscosity of 800 to 1300 mPa·s at 25° C. and a hydroxyl value of 173 to 193 mgKOH / g.

[0057] In one embodiment, the preparation method of the modified talc is:

[0058] (1) treating talc powder with plasma to obtain pretreated talc powder;

[0059] (2) adding pretreated talcum powder and citric acid to the sulfuric acid solution, stirring evenly, and then adding γ-glycidyloxypropyltrimethoxysilane, stirring evenly to obtain a precursor solution;

[0060] (3) adding 4-vinylbenzeneboronic acid, boric acid and azobisisobutyronitrile to hydroxyl-terminated polydimethylsiloxane, reacting at 80-95° C. for 2-6 hours to obtain a modified solution;

[0061] (4) Add the modified liquid to the precursor liquid, stir evenly at 65-80° C., ultrasonically treat, filter, and dry to obtain modified talc.

[0062] The present invention improves the dispersing effect of talcum powder in the system by modifying talcum powder, so that it can be evenly dispersed in the system without agglomeration, and the modified talcum powder can inhibit the thermal expansion of the potting glue matrix and the movement of the molecular chain segments through physical filling and chemical bonding, and reduce the thermal aging and dimensional change of the material. In addition, the flaky structure of talcum powder has a good mechanical reinforcement effect, which can enhance the rigidity and high temperature resistance of the potting glue, and the surface polarity and wettability of the modified talcum powder are enhanced, so that it is fully in contact with the organic components of the potting glue and forms a stronger interface bonding, effectively improving the bonding strength of the potting glue, and making it easier to form a filler filling network structure with silicon micropowder and gas silicon in the system at high temperature. As an inorganic filler, talcum powder can play a role in heat insulation and stable structure, effectively reducing the thermal degradation of polymer matrices such as organic siloxane, and effectively improving the heat resistance of the potting glue.

[0063] In one embodiment, the voltage of the plasma treatment is 220V, the power is 600-800W, and the time is 2-5min.

[0064] In one embodiment, the mass ratio of the pretreated talc, citric acid, sulfuric acid solution, and γ-glycidyloxypropyltrimethoxysilane is 1: (0.05-0.2): (2-5): (0.02-0.08).

[0065] In one embodiment, the mass ratio of 4-vinylbenzeneboronic acid, boric acid, azobisisobutyronitrile, and hydroxyl-terminated polydimethylsiloxane is (0.1-0.2): (0.1-0.2): (0.02-0.05): 1;

[0066] The mass ratio of the modifying liquid to the precursor liquid is 1:(8-12).

[0067] In one embodiment, the crosslinking agent includes at least one of methyl tributylacetoximate silane, phenyl tributylacetoximate silane, and methyl vinyl dibutyl ketone oxime silane;

[0068] The catalyst includes at least one of dibutyltin dilaurate, dibutyltin diacetate, and stannous octoate;

[0069] The coupling agent includes at least one of 3-isocyanate propyl triethoxy silane and γ-isocyanate propyl trimethoxy silane.

[0070] An embodiment of the present application provides a method for preparing a heat-resistant potting adhesive, comprising the following steps:

[0071] The alkoxy-terminated polydimethylsiloxane, the plasticizer and the cross-linking agent are mixed evenly, and then the modified talcum powder, the fumed silica and the silicon micropowder are added and mixed evenly, and finally the coupling agent and the catalyst are added and mixed evenly to obtain the heat-resistant potting adhesive.

[0072] An embodiment of the present application provides an application of a heat-resistant potting compound in electronic components and optical devices.

[0073] The following examples are provided to facilitate understanding of the present invention. These examples are not provided to limit the scope of the claims.

[0074] Example 1

[0075] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane-1, 22 parts of a plasticizer, 16 parts of modified talcum powder, 4 parts of fumed silica, 2 parts of silicon micropowder, 8 parts of potassium 3-phenylsulfonylbenzenesulfonate, 4 parts of a crosslinking agent, 3 parts of a coupling agent, and 0.4 parts of a catalyst.

[0076] The plasticizer comprises vinyl silicone oil-1 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-1 to the cashew nut shell oil phenolic resin is 4:1.

[0077] The preparation method of the modified talcum powder is:

[0078] (1) placing talc powder in a plasma reaction vessel, treating it at a voltage of 220 V, normal temperature and pressure (one atmosphere) at a power of 800 W for 5 min to obtain pretreated talc powder;

[0079] (2) Add pretreated talcum powder and citric acid to 1 mol / L sulfuric acid solution, stir evenly at 300 rpm, then add γ-glycidyloxypropyltrimethoxysilane, stir at 300 rpm for 30 min at 50°C to obtain a precursor solution; the mass ratio of the pretreated talcum powder, citric acid, sulfuric acid solution, and γ-glycidyloxypropyltrimethoxysilane is 1:0.15:4:0.05.

[0080] (3) adding 4-vinylbenzene boronic acid, boric acid, and azobisisobutyronitrile to hydroxyl-terminated polydimethylsiloxane, reacting at 90° C. for 4 hours to obtain a modified solution; the mass ratio of the 4-vinylbenzene boronic acid, boric acid, azobisisobutyronitrile, and hydroxyl-terminated polydimethylsiloxane is 0.15:0.15:0.04:1;

[0081] (4) adding the modifying liquid to the precursor liquid, stirring at 75° C. for 2 h, ultrasonically treating at 500 W for 25 min, filtering, and drying to obtain modified talc; the mass ratio of the modifying liquid to the precursor liquid is 1:10.

[0082] The preparation method of the heat-resistant potting glue comprises the following steps:

[0083] Alkoxy-terminated polydimethylsiloxane-1, a plasticizer, and a cross-linking agent are mixed evenly, and then modified talcum powder, fumed silica, and silicon powder are added and mixed evenly. Finally, a coupling agent and a catalyst are added and mixed evenly to obtain a heat-resistant potting adhesive.

[0084] Example 2

[0085] The difference between Example 2 and Example 1 is that the amount of raw materials used is different, and the other aspects are the same.

[0086] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane-1, 18 parts of a plasticizer, 20 parts of modified talcum powder, 2 parts of fumed silica, 3 parts of silicon micropowder, 6 parts of potassium 3-phenylsulfonylbenzenesulfonate, 5 parts of a crosslinking agent, 1 part of a coupling agent, and 0.5 parts of a catalyst.

[0087] Example 3

[0088] The difference between Example 3 and Example 1 is that the amount of raw materials used is different, and the other aspects are the same.

[0089] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane-1, 25 parts of a plasticizer, 14 parts of modified talcum powder, 5 parts of fumed silica, 1 part of silicon micropowder, 10 parts of potassium 3-phenylsulfonylbenzenesulfonate, 3 parts of a crosslinking agent, 4 parts of a coupling agent, and 0.2 parts of a catalyst.

[0090] Example 4

[0091] The difference between Example 4 and Example 1 is that Example 4 uses an equal amount of alkoxy-terminated polydimethylsiloxane-2 to replace alkoxy-terminated polydimethylsiloxane-1, and the other parts are the same.

[0092] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane-2, 22 parts of a plasticizer, 16 parts of modified talcum powder, 4 parts of fumed silica, 2 parts of silicon micropowder, 8 parts of potassium 3-phenylsulfonylbenzenesulfonate, 4 parts of a crosslinking agent, 3 parts of a coupling agent, and 0.4 parts of a catalyst.

[0093] Example 5

[0094] The difference between Example 5 and Example 1 is that Example 5 uses an equal amount of alkoxy-terminated polydimethylsiloxane-3 to replace alkoxy-terminated polydimethylsiloxane-1, and the other parts are the same.

[0095] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane-3, 22 parts of a plasticizer, 16 parts of modified talcum powder, 4 parts of fumed silica, 2 parts of silicon micropowder, 8 parts of potassium 3-phenylsulfonylbenzenesulfonate, 4 parts of a crosslinking agent, 3 parts of a coupling agent, and 0.4 parts of a catalyst.

[0096] Example 6

[0097] The difference between Example 6 and Example 1 is that Example 6 uses an equal amount of alkoxy-terminated polydimethylsiloxane-4 to replace alkoxy-terminated polydimethylsiloxane-1, and the other parts are the same.

[0098] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane-4, 22 parts of a plasticizer, 16 parts of modified talcum powder, 4 parts of fumed silica, 2 parts of silicon micropowder, 8 parts of potassium 3-phenylsulfonylbenzenesulfonate, 4 parts of a crosslinking agent, 3 parts of a coupling agent, and 0.4 parts of a catalyst.

[0099] Example 7

[0100] The difference between Example 7 and Example 1 is that an equal amount of vinyl silicone oil-2 is used to replace vinyl silicone oil-1, and the other contents are the same.

[0101] The plasticizer comprises vinyl silicone oil-2 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-2 to the cashew nut shell oil phenolic resin is 4:1.

[0102] Example 8

[0103] The difference between Example 8 and Example 1 is that an equal amount of vinyl silicone oil-3 is used to replace vinyl silicone oil-1, and the other contents are the same.

[0104] The plasticizer comprises vinyl silicone oil-3 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-3 to the cashew nut shell oil phenolic resin is 4:1.

[0105] Example 9

[0106] The difference between Example 9 and Example 1 is that an equal amount of vinyl silicone oil-4 is used to replace vinyl silicone oil-1, and the other contents are the same.

[0107] The plasticizer comprises vinyl silicone oil-4 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-4 to the cashew nut shell oil phenolic resin is 4:1.

[0108] Example 10

[0109] The difference between Example 10 and Example 1 is that the mass ratio of vinyl silicone oil-1 and cashew nut shell oil phenolic resin is different, and the other parts are the same.

[0110] The plasticizer comprises vinyl silicone oil-1 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-1 to the cashew nut shell oil phenolic resin is 3:1.

[0111] Embodiment 11

[0112] The difference between Example 11 and Example 1 is that the mass ratio of vinyl silicone oil-1 and cashew nut shell oil phenolic resin is different, and the other parts are the same.

[0113] The plasticizer comprises vinyl silicone oil-1 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-1 to the cashew nut shell oil phenolic resin is 5:1.

[0114] Comparative Example 1

[0115] The difference between Comparative Example 1 and Example 1 is that the plasticizer in Comparative Example 1 is a single vinyl silicone oil-1, and the other parts are the same.

[0116] The plasticizer described in this comparative example is vinyl silicone oil-1.

[0117] Comparative Example 2

[0118] The difference between Comparative Example 2 and Example 1 is that the plasticizer of Comparative Example 2 is a single cashew nut shell oil phenolic resin, and the others are the same.

[0119] The plasticizer described in this comparative example is cashew nut shell oil phenolic resin.

[0120] Comparative Example 3

[0121] The difference between Comparative Example 3 and Example 1 is that the plasticizer of Comparative Example 3 is conventional dimethyl silicone oil in the art, and the other aspects are the same.

[0122] The plasticizer described in this comparative example is dimethyl silicone oil, and the viscosity of the dimethyl silicone oil at 25° C. is 5000 mPa·s (brand number 201-5000, Zhejiang Rongli High-tech).

[0123] Comparative Example 4

[0124] The difference between Comparative Example 4 and Example 1 is that the mass ratio of vinyl silicone oil-1 and cashew nut shell oil phenolic resin is different, and the others are the same.

[0125] The plasticizer comprises vinyl silicone oil-1 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-1 to the cashew nut shell oil phenolic resin is 9:1.

[0126] Comparative Example 5

[0127] The difference between Comparative Example 5 and Example 1 is that the mass ratio of vinyl silicone oil-1 and cashew nut shell oil phenolic resin is different, and the others are the same.

[0128] The plasticizer comprises vinyl silicone oil-1 and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil-1 to the cashew nut shell oil phenolic resin is 1:1.

[0129] Comparative Example 6

[0130] The difference between Comparative Example 6 and Example 1 is that Comparative Example 6 uses an equal amount of talcum powder to replace the modified talcum powder, and the other contents are the same.

[0131] A heat-resistant potting adhesive comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane-1, 22 parts of a plasticizer, 16 parts of talcum powder, 4 parts of fumed silica, 2 parts of silicon micropowder, 8 parts of potassium 3-phenylsulfonylbenzenesulfonate, 4 parts of a crosslinking agent, 3 parts of a coupling agent, and 0.4 parts of a catalyst.

[0132] Comparative Example 7

[0133] The difference between Comparative Example 7 and Example 1 is that the preparation method of the modified talc powder described in Comparative Example 7 is different from that in Example 1, and the other parts are the same.

[0134] The preparation method of the modified talcum powder is:

[0135] (1) placing talc powder in a plasma reaction vessel, treating it at a voltage of 220 V, normal temperature and pressure (one atmosphere) at a power of 800 W for 5 min to obtain pretreated talc powder;

[0136] (2) Add pretreated talc and citric acid to 1 mol / L sulfuric acid solution, stir evenly at 300 rpm, then add γ-glycidyloxypropyltrimethoxysilane, stir at 300 rpm for 30 min at 50°C, filter, and dry to obtain modified talc; the mass ratio of the pretreated talc, citric acid, sulfuric acid solution, and γ-glycidyloxypropyltrimethoxysilane is 1:0.15:4:0.05.

[0137] Test Case

[0138] The tensile strength was measured according to the method described in GB / T 528-2009. The initial tensile strength was recorded as L0. The potting glue of the embodiment and the comparative example was placed at 90°C for 14 days, and its tensile strength was measured and recorded as L1. The change rate of tensile strength was calculated, and the change rate of tensile strength = (L0-L1) / L0*100%.

[0139] Table 1

[0140]

[0141]

[0142] It can be seen from Table 1 that the potting adhesive of the present invention has excellent bonding performance and heat resistance.

[0143] By comparing Example 1 with Comparative Examples 1 to 5, it can be seen that the present invention adopts vinyl silicone oil and cashew nut shell oil phenolic resin in a mass ratio of (3 to 5): 1, which significantly improves the bonding performance and heat resistance, wherein the vinyl silicone oil and cashew nut shell oil phenolic resin have obvious synergistic effect.

[0144] By comparing Example 1 with Comparative Examples 6 to 7, it can be seen that the modified talc powder of the present invention can significantly improve the bonding performance and heat resistance.

[0145] By comparing Example 1 with Examples 4 to 7, it can be seen that the present invention uses alkoxy-terminated polydimethylsiloxane with a viscosity of 20,000 to 35,000 mPa·s to further improve the bonding performance and heat resistance.

[0146] By comparing Example 1 with Examples 7 to 9, it can be seen that the present invention uses vinyl silicone oil with a vinyl content of 0.18 to 0.3 wt% and a viscosity of 1000 to 5000 mPa·s, which further improves the bonding performance and heat resistance.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A heat-resistant potting adhesive, characterized in that: The invention comprises the following components in parts by weight: 100 parts of alkoxy-terminated polydimethylsiloxane, 18 to 25 parts of plasticizer, 14 to 20 parts of modified talc, 2 to 5 parts of fumed silica, 1 to 3 parts of silicon micropowder, 6 to 10 parts of potassium 3-phenylsulfonylbenzenesulfonate, 2 to 5 parts of crosslinking agent, 2 to 4 parts of coupling agent, and 0.2 to 0.5 parts of catalyst; The plasticizer comprises vinyl silicone oil and cashew nut shell oil phenolic resin, and the mass ratio of the vinyl silicone oil to the cashew nut shell oil phenolic resin is (3-5):

1.

2. The heat-resistant potting adhesive according to claim 1, characterized in that: The viscosity of the alkoxy-terminated polydimethylsiloxane at 25° C. is 20,000 to 35,000 mPa·s.

3. The heat-resistant potting adhesive according to claim 1, characterized in that: The viscosity of the vinyl silicone oil at 25° C. is 1000 to 5000 mPa·s, and the vinyl content of the vinyl silicone oil is 0.18 to 0.3 wt %.

4. The heat-resistant potting adhesive according to claim 1, characterized in that: The cashew nut shell oil phenolic resin has a viscosity of 800 to 1300 mPa·s at 25° C. and a hydroxyl value of 173 to 193 mgKOH / g.

5. The heat-resistant potting adhesive according to claim 1, characterized in that: The preparation method of the modified talcum powder is: (1) treating talc powder with plasma to obtain pretreated talc powder; (2) adding pretreated talcum powder and citric acid to the sulfuric acid solution, stirring evenly, and then adding γ-glycidyloxypropyltrimethoxysilane, stirring evenly to obtain a precursor solution; (3) adding 4-vinylbenzeneboronic acid, boric acid and azobisisobutyronitrile to hydroxyl-terminated polydimethylsiloxane, reacting at 80-95° C. for 2-6 hours to obtain a modified solution; (4) Add the modified liquid to the precursor liquid, stir evenly at 65-80° C., ultrasonically treat, filter, and dry to obtain modified talc.

6. The heat-resistant potting adhesive according to claim 5, characterized in that: The voltage of the plasma treatment is 220V, the power is 600-800W, and the time is 2-5min.

7. The heat-resistant potting adhesive according to claim 5, characterized in that: The mass ratio of the pretreated talcum powder, citric acid, sulfuric acid solution and γ-glycidyloxypropyltrimethoxysilane is 1:(0.05-0.2):(2-5):(0.02-0.08).

8. The heat-resistant potting adhesive according to claim 5, characterized in that: The mass ratio of 4-vinylbenzeneboronic acid, boric acid, azobisisobutyronitrile and hydroxyl-terminated polydimethylsiloxane is (0.1-0.2): (0.1-0.2): (0.02-0.05): 1; The mass ratio of the modifying liquid to the precursor liquid is 1:(8-12).

9. The heat-resistant potting adhesive according to claim 1, characterized in that: The crosslinking agent includes at least one of methyl tributylacetoximate silane, phenyl tributylacetoximate silane, and methyl vinyl dibutyl ketone oxime silane; The catalyst includes at least one of dibutyltin dilaurate, dibutyltin diacetate, and stannous octoate; The coupling agent includes at least one of 3-isocyanate propyl triethoxy silane and γ-isocyanate propyl trimethoxy silane.

10. The method for preparing the heat-resistant potting adhesive according to any one of claims 1 to 9, characterized in that: The following steps are involved: The alkoxy-terminated polydimethylsiloxane, the plasticizer and the cross-linking agent are mixed evenly, and then the modified talcum powder, the fumed silica and the silicon micropowder are added and mixed evenly, and finally the coupling agent and the catalyst are added and mixed evenly to obtain the heat-resistant potting adhesive.

11. Use of the heat-resistant potting adhesive according to any one of claims 1 to 9 in electronic components and optical devices.

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