Two-component condensation type silicone pouring sealant composition, preparation method and pouring sealant

Abstract

The application belongs to the technical field of organic silicon, and particularly relates to a two-component condensation type organic silicon pouring sealant composition, a preparation method and a pouring sealant. The two-component condensation type organic silicon pouring sealant composition provided by the application has the advantages of fast overall curing speed after uniform mixing, good heat conduction performance and good flame retardance, and can be used to solve the technical problems of low adhesion to various plastic substrates, low heat conduction performance, low flame retardance grade and easy thickening during storage of the two-component condensation type organic silicon pouring sealant in the prior art, and can be widely applied to pouring of photovoltaic inverters and optimizers, and pouring of high-power electronic appliances and components.

Description

Technical Field

[0001] This application belongs to the field of organosilicon technology, and particularly relates to a two-component condensation-type organosilicon potting compound composition, its preparation method, and the potting compound. Background Technology

[0002] When single-component condensation-type silicone potting compounds are applied to a thickness of several millimeters or more, they suffer from slow overall curing, leading to low production efficiency and increased production costs for downstream customers. Two-component condensation-type silicone potting compounds can significantly overcome this drawback. Depending on the mixing ratio, two-component condensation-type silicone products are mainly available with an A:B ratio of 10:1 and 1:1. The 1:1 ratio product offers improved application stability compared to the 10:1 product, avoiding significant changes in potting compound performance due to fluctuations in the mixing ratio. With societal development, customers have placed higher demands on products. Currently available two-component condensation-type 1:1 products generally suffer from poor adhesion to various substrates, low thermal conductivity, low flame retardancy, and a tendency to thicken during storage. Summary of the Invention

[0003] In view of this, this application provides a two-component condensation-type silicone potting compound composition, preparation method, and potting compound to solve the technical problems of low adhesion, low thermal conductivity, low flame retardancy, and easy thickening during storage of condensation-type two-component silicone potting compounds in the prior art.

[0004] The first aspect of this application provides a two-component condensation-type silicone potting compound composition, comprising component A and component B.

[0005] Component A of the adhesive includes hydroxyl-terminated polydimethylsiloxane, powder treatment agent, filler, and catalyst;

[0006] Component B of the adhesive includes silane-terminated liquid polybutadiene, fillers, pigments, crosslinking agents, chain extenders, and coupling agents.

[0007] Preferably, the powder treatment agent is selected from one of tetra(triethanolamine)zirconium, neoalkoxytris(p-aminophenoxy)zirconium ester, neoalkoxytris(ethylenediaminon-N-ethoxy)zirconium ester, neoalkoxytris(acryloyloxy)zirconium ester, bisne-alkoxybis(4-aminobenzoic acid acryloyl)zirconium ester, neoalkoxytris(methacryloyloxy)zirconium ester, neoalkoxytris(dioctylphosphoacryloyl)zirconium ester, neoalkoxytris(dodecylbenzenesulfonyl)zirconium ester, and neoalkoxytris(dioctylpyrophosphoacryloyl)zirconium ester.

[0008] Preferably, in component A of the adhesive, the catalyst is an organotin catalyst.

[0009] Preferably, the two-component condensation-type silicone composition comprises 0.8 to 1.2 parts by weight of component A and 1 part by weight of component B.

[0010] Preferably, by weight, component A of the adhesive comprises 5-20 parts by weight of hydroxyl-terminated polydimethylsiloxane, 0.1-0.5 parts by weight of powder treatment agent, 80-95 parts by weight of hydrophobically treated filler, and 0.005-0.05 parts by weight of organotin catalyst;

[0011] Component B of the adhesive comprises 5-10 parts by weight of silane-terminated liquid polybutadiene, 80-95 parts by weight of hydrophobically treated filler, 0.1-2 parts by weight of pigment, 0.1-1.0 parts by weight of crosslinking agent, 0.5-2.5 parts by weight of chain extender, and 0.1-2 parts by weight of silane coupling agent.

[0012] Preferably, the organotin catalyst is selected from one of dimethyltin oleate and diacetylacetonate dibutyltin;

[0013] In component B of the adhesive, the crosslinking agent is selected from one of 1,2-bis(trimethoxysilyl)ethane and 1,2-bis(triethoxysilyl)ethane;

[0014] The chain extender is selected from one of dimethyldimethoxysiloxane, dimethyldiethoxysiloxane, methylvinyldimethoxysiloxane, and methylvinyldiethoxysiloxane;

[0015] The coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-β-(aminoethyl)-γ-aminopropyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropyltriethoxysilane.

[0016] Both components A and B of the adhesive contain fillers;

[0017] The filler is selected from at least one of alumina, zinc oxide, aluminum hydroxide, magnesium hydroxide, boron nitride, and aluminum nitride, wherein alumina is mandatory;

[0018] The pigment is selected from either carbon black paste or titanium white paste;

[0019] The second aspect of this application provides a method for preparing a two-component condensation-type silicone potting compound composition, which is used to prepare the above-mentioned two-component condensation-type silicone potting compound composition. The preparation method includes the following steps:

[0020] Hydroxyl-terminated polydimethylsiloxane and powder treatment agent are added to a dynamic mixer and stirred continuously until homogeneous. Then, filler is added and stirred until homogeneous. The mixture is kept at a constant temperature of 100-130°C for 2-3 hours under a vacuum of ≥0.08MPa. The material is then cooled to room temperature to obtain component A adhesive semi-finished product. Catalyst is then added and stirred until homogeneous under a vacuum of ≥0.08MPa to obtain component A adhesive. During all the stirring processes, the main mixer frequency and dispersion frequency are maintained at 15-30Hz.

[0021] The filler is baked in an oven at any constant temperature within the range of 100~130℃ for 2~3 hours. After baking, it is cooled to 60~80℃. Silane-terminated liquid polybutadiene, pigment, crosslinking agent, chain extender, and coupling agent are added to a dynamic mixer and stirred evenly. Then the filler is added and stirred evenly. Vacuum is then turned on, and after the vacuum degree is greater than or equal to 0.08MPa, the valve is closed to keep the system in a closed and vacuum state. The temperature is raised to any specific temperature within the range of 60~80℃, and the temperature is maintained and stirred for 2~3 hours. After baking, the material is cooled to room temperature to obtain component B adhesive. During the preparation of component B adhesive, the stirring frequency of the main unit and the dispersion frequency are maintained at 10~30Hz.

[0022] A third aspect of this application provides a photovoltaic inverter comprising the above-described two-component condensation-type silicone potting compound composition.

[0023] The fourth aspect of this application provides a photovoltaic optimizer potting compound, comprising the above-described two-component condensation-type silicone potting compound composition.

[0024] The fifth aspect of this application provides a potting compound for high-power electronic appliances and components, including the above-mentioned two-component condensation-type silicone potting compound composition.

[0025] It should be noted that the potting compound composition provided in this application has excellent adhesion properties to a variety of difficult-to-bond plastic substrates such as PC, PET, PBT, PA66, ABS and PVC, as well as aluminum, stainless steel or other metal substrates, and can therefore be widely used in the fields of electronics, electrical engineering, photovoltaics and so on.

[0026] In summary, this application provides a two-component condensation-type silicone potting compound composition, preparation method, and potting compound. The two-component condensation-type silicone composition includes component A and component B. Component A includes hydroxyl-terminated polydimethylsiloxane, a powder treatment agent, filler, and catalyst. Component B includes silane-terminated liquid polybutadiene, a powder treatment agent, filler, pigment, crosslinking agent, chain extender, and coupling agent. After uniform mixing, component A and component B in the two-component condensation-type silicone potting compound composition can be rapidly cured. Furthermore, during the curing process, because the silane-terminated liquid polybutadiene contains a large number of organic segments that are "similar and compatible" with the polymer backbone segments of various plastic substrates, and the selected crosslinking agent also has high reactivity, the silane coupling agent also participates in the reaction. The curing process generates a large molecular weight tackifying molecular structure, improving the adhesive strength of the cured potting compound. It is suitable for bonding various difficult-to-bond plastics and metal substrates. During the preparation of components A and B, a powder treatment agent is added via blending. On one hand, the addition of the treatment agent provides a "secondary treatment" to the powder filler. By reacting and combining with residual moisture or hydroxyl groups on the filler surface, and fully reacting under high temperature conditions, the compatibility between the powder and the base polymer is greatly improved, the viscosity of components A and B is reduced, and the workability, thermal conductivity, and flame retardancy of the potting compound are enhanced. Furthermore, experiments have shown that the performance of the two-component condensation-type silicone potting compound composition provided in this application does not change significantly after being sealed for six months. The crosslinking agent, chain extender, and coupling agent in component B all serve as a "secondary treatment" for the powder filler. On the other hand, the multiple reactivity of the added powder treatment agent allows the final composition to further improve its bonding and adhesion to the substrate after curing, thereby solving the technical problems of poor adhesion, low thermal conductivity, and low flame retardancy of existing thermally conductive and flame-retardant condensation-type two-component silicone potting compounds. Detailed Implementation

[0027] This application provides a two-component condensation-type silicone potting compound composition, preparation method, and potting compound, which solves the technical problems of low adhesion, low thermal conductivity, low flame retardancy, and easy thickening during storage of existing two-component condensation-type silicone potting compounds.

[0028] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] Example 1

[0030] Given that existing two-component condensation-type silicone potting compounds require the addition of large amounts of thermally conductive fillers and flame-retardant fillers to achieve high thermal conductivity and flame retardant properties, which easily leads to poor adhesion, poor handling performance, and thickening during storage, Example 1 of this application provides a two-component condensation-type silicone composition. The two-component condensation-type silicone composition includes component A and component B. Component A includes hydroxyl-terminated polydimethylsiloxane, powder treatment agent, filler, and catalyst. Component B includes silane-terminated liquid polybutadiene, filler, pigment, crosslinking agent, chain extender, and coupling agent. The two-component condensation-type silicone potting compound composition, in which component A and component B are uniformly mixed, can cure rapidly. Furthermore, during the curing process, due to the large number of organic segments in the silane-terminated liquid polybutadiene that are structurally similar and compatible with the organic segments of difficult-to-bond plastic substrates, the crosslinking agent also exhibits high reactivity, and the silane coupling agent simultaneously participates in the reaction. This curing process generates a larger molecular weight tackifying molecule structure, improving the adhesive strength of the cured potting compound. It is suitable for bonding various difficult-to-bond substrates and can be used to solve the problems of existing thermally conductive and flame-retardant condensation-type two-component silicone compounds. The problem of poor adhesion of the potting compound is addressed by adding zirconate esters and alkoxysiloxanes with different structures to both components A and B. After the addition of the treatment agents, the powder filler is "treated" in a "secondary manner". By reacting and combining with the residual moisture or hydroxyl groups on the surface of the filler, the reaction is fully carried out under high temperature conditions, which further improves the compatibility between the powder and the base polymer, reduces the viscosity of A and B compounds, and improves the workability, thermal conductivity and flame retardancy of the potting compound. At the same time, the performance of the two-component condensation type silicone potting compound provided in this application does not change significantly after being sealed for half a year.

[0031] Preferably, in the A component of the two-component condensation-type silicone composition, the catalyst is an organotin catalyst. The initial curing time of the two-component condensation-type silicone composition with a thickness of 5 cm is 30-40 minutes, and it can achieve a certain hardness, which improves the production efficiency of downstream customers and reduces production costs. For the organotin catalyst, this application selects one of dimethyl tin oleate or diacetylacetonate dibutyltin. The organotin catalyst, combined with a highly active crosslinking agent and coupling agent, enables the two-component condensation-type silicone potting compound to have a faster overall curing speed.

[0032] Preferably, the B component of the two-component condensation-type silicone composition further includes a chain extender. The chain extender results in a lower hardness (below 60A) and a higher elongation at break (above 200%) after curing, leading to better elasticity and toughness of the potting compound. For the chain extender, this application selects one or more of dimethyldimethoxysiloxane, dimethyldiethoxysiloxane, methylvinyldimethoxysiloxane, and methylvinyldiethoxysiloxane.

[0033] Examples 2-5 and Comparative Example 1

[0034] Examples 2-5 of this application provide a method for preparing the two-component condensation type organosilicon composition described in Example 1. The preparation method includes the preparation of component A adhesive and component B adhesive. The components of component A adhesive and component B adhesive in the preparation method are shown in Tables 1-2.

[0035] The preparation of component A adhesive involves adding hydroxyl-terminated polydimethylsiloxane and powder treatment agent to a 5-liter dynamic mixer according to the proportions shown in Table 1 and stirring until homogeneous. Then, filler is added and stirred until homogeneous. Simultaneously, a vacuum is maintained at a pressure greater than or equal to 0.08 MPa and a material temperature of 100–130°C for 2–3 hours. After cooling, a catalyst is added, and the mixture is stirred again until homogeneous. The mixture is then sealed and packaged to obtain component A adhesive. During the stirring process, the revolution speed and dispersion speed are maintained at 10–30 Hz. In Table 1-2, hydroxyl-terminated... The viscosity of polydimethylsiloxane at room temperature (25±2℃) is 100~400mPa·s, the particle size (D50) of alumina is 10~20μm, the particle size (D50) of zinc oxide is 1μm, the particle size (D50) of aluminum hydroxide is 20μm, the particle size (D50) of boron nitride is 30μm, the particle size (D50) of magnesium hydroxide is 18μm, the molecular weight of silane-terminated liquid polybutadiene is 1000~2000, and the viscosity of methyl-terminated polydimethylsiloxane at room temperature (25±2℃) is 50mPa·s.

[0036] The preparation of component B adhesive involves adding silane-terminated liquid polybutadiene, pigment, crosslinking agent, chain extender, and coupling agent to a 5-liter dynamic mixer in the proportions shown in Table 1 and stirring until homogeneous. Then, filler is added and stirred until homogeneous. Vacuum is turned on and maintained at a vacuum degree greater than or equal to 0.08 MPa, and the system is kept in a closed state. Stirring is carried out for 2 to 3 hours at a material temperature of 60 to 80°C. After cooling, component B is obtained by sealing and packaging. During the stirring process, the revolution speed and dispersion speed are maintained at 10 to 30 Hz.

[0037] The preparation method provided in this application is to prepare a two-component condensation-type organosilicon composition under vacuum and at a high temperature, thereby making the moisture content in the two-component condensation-type organosilicon composition very low, which is beneficial to improving the storage stability of the two-component condensation-type organosilicon potting compound composition.

[0038]

[0039] Table 1

[0040]

[0041] Table 2

[0042] Experimental Example 1

[0043] Experimental Example 1 of this application provides performance tests of the two-component condensation-type silicone potting compound compositions described in Examples 2-5 and Comparative Example 1. The performance tests include appearance, curing speed, mechanical properties, adhesive properties, thermal conductivity, flame retardancy, storage properties, and aging. The test results are shown in Tables 3-4.

[0044]

[0045] Table 3

[0046]

[0047] Table 4

[0048] As shown in Table 3, the two-component condensation-type silicone potting compounds provided in Examples 2-5 can bond commonly used metals such as Al and stainless steel, as well as various plastics such as PC, PET, PBT, PA66, ABS, and PVC, which are difficult to bond, after curing. In particular, the two-component condensation-type silicone compounds provided in Examples 2-5 exhibit cohesive failure after bonding, indicating that the bonding strength of the two-component condensation-type silicone compounds provided in Examples 2-5 is greater than the internal stress between difficult-to-bond plastic substrates such as PC, PET, PBT, PA66, ABS, and PVC, and metal substrates such as stainless steel and aluminum. The two-component condensation-type silicone compound provided in Example 6 has slightly lower bonding strength. This indicates that during the curing process of the two-component condensation-type silicone compounds provided in this application, due to the presence of a large number of hydrocarbon-based organic segments in the silane-terminated liquid polybutadiene structure, which react with crosslinking agents and silane coupling agents to generate a larger molecular weight tackifying molecular structure, the bonding strength of the cured potting compound can be improved, making it suitable for bonding various plastic and metal substrates.

[0049] As can be seen from Table 3, the curing speed of the two-component condensation-type silicone composition provided in Example 6 after applying 5 cm of adhesive exceeds 2 hours, while the curing speed of the two-component condensation-type silicone compositions provided in Examples 2-5 is 30-40 minutes. This indicates that the combination of organotin catalyst with highly active crosslinking agents and other additives can improve the curing speed of the two-component condensation-type silicone composition, improve the production efficiency of downstream customers, reduce production costs, and meet the production needs of customers.

[0050] As can be seen from Table 3, the two-component condensation-type silicone composition provided in Comparative Example 1 has a Shore hardness greater than 85, a tensile strength of 1.5 MPa, and an elongation at break of 50% after curing. In contrast, the two-component condensation-type silicone compositions provided in Examples 2-5 have a Shore hardness of 35-52, a tensile strength of 2.2-2.8 MPa, and an elongation at break of 210-310% after curing. This indicates that the addition of chain extenders such as dimethyldimethoxysiloxane can improve the toughness of the two-component condensation-type silicone composition.

[0051] As can be seen from Table 3, the thermal conductivity of the two-component condensation-type silicone compositions provided in Examples 2-6 is between 2.0 and 4.5 W / m·K, and the flame retardant rating is V0. This indicates that the addition of fillers gives the potting compound excellent thermal conductivity and flame retardant properties, and the addition of powder treatment agent makes the potting compound have good leveling properties, which facilitates operation and construction.

[0052] As shown in Table 4, the two-component condensation-type silicone potting compound adhesive substrate sample provided in Comparative Example 1 became severely sticky and soft after 1000 hours of damp heat aging at 85℃ / 85% humidity, resulting in interfacial damage to aluminum bonding. This clearly indicates degradation after the aging test. In contrast, the two-component condensation-type silicone potting compound adhesive substrate samples provided in Examples 2-5 showed no significant changes after 1000 hours of aging at 85℃ / 85% humidity. This suggests that the selection of crosslinking agent and catalyst has a significant negative impact on the aging performance of the adhesive. Furthermore, when subjected to high and low temperature shock tests at -40 to 100℃, there was no significant difference between Examples 2-5 and Comparative Example 1. This indicates that the changes in composition in Examples 2-5 did not affect the adaptability of the potting compound under drastic temperature changes.

[0053] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A two-component condensation-type silicone potting compound composition, characterized in that, Includes component A adhesive and component B adhesive; Component A of the adhesive includes hydroxyl-terminated polydimethylsiloxane, powder treatment agent, filler, and catalyst; Component B of the adhesive includes silane-terminated liquid polybutadiene, fillers, pigments, crosslinking agents, chain extenders, and coupling agents; The hydroxyl-terminated polydimethylsiloxane has the structural formula shown in Formula 1, and its viscosity range is 100~400 mPa·s at a temperature of 23±2℃. Formula 1; In Equation 1, n is an integer; The powder treatment agent is selected from tetra(triethanolamine)zirconium, bisnealkoxybis(4-aminobenzoic acid acyloxy)zirconate, neoalkoxytris(dioctylphosphoacyloxy)zirconate, and neoalkoxytris(dodecylbenzenesulfonyloxy)zirconate. The filler is selected from at least one of alumina and zinc oxide, aluminum hydroxide, magnesium hydroxide, and boron nitride, and the filler is a hydrophobic filler. The catalyst is selected from one of dimethyltin oleate and diacetylacetonyl dibutyltin. The structural formula of silane-terminated liquid polybutadiene is shown in Formula 2. Formula 2; In Formula 2, R1 is —CH2CH2CH(Si(OR2)3)CH3 or —CH2CH2CH2CH2(Si(OR2)3), R2 is methyl or ethyl, and x, y, z are integers; The pigment is selected from either carbon black paste or titanium white paste; The crosslinking agent is selected from one of 1,2-bis(trimethoxysilyl)ethane and 1,2-bis(triethoxysilyl)ethane; The chain extender is selected from one of dimethyldimethoxysiloxane, dimethyldiethoxysiloxane, methylvinyldimethoxysiloxane, and methylvinyldiethoxysiloxane; The coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltriethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. The two-component condensation-type silicone potting compound composition comprises 0.8 to 1.2 parts by weight of component A and 1 part by weight of component B, calculated in parts by weight. Component A of the adhesive includes 5-20 parts by weight of hydroxyl-terminated polydimethylsiloxane, 0.1-0.5 parts by weight of powder treatment agent, 80-95 parts by weight of hydrophobically treated filler, and 0.005-0.05 parts by weight of catalyst; Component B of the adhesive includes 5-10 parts by weight of silane-terminated liquid polybutadiene, 80-95 parts by weight of hydrophobically treated filler, 0.1-2 parts by weight of pigment, 0.1-1.0 parts by weight of crosslinking agent, 0.5-2.5 parts by weight of chain extender, and 0.1-2 parts by weight of coupling agent.

2. The method for preparing a two-component condensation-type silicone potting compound composition according to claim 1, characterized in that, The preparation method includes steps for preparing component A adhesive and component B adhesive: The steps for preparing component A adhesive include: adding hydroxyl-terminated polydimethylsiloxane and powder treatment agent into a dynamic mixer and stirring evenly; then adding filler and stirring evenly; maintaining the mixture at a constant temperature of 100~130℃ for 2~3 hours under a vacuum degree greater than or equal to 0.08MPa; and then cooling the material to room temperature to obtain a component A adhesive semi-finished product; further adding catalyst and stirring evenly under a vacuum degree greater than or equal to 0.08MPa to obtain component A adhesive. During the stirring process of preparing component A adhesive, the main unit frequency and dispersion frequency are maintained at 15~30Hz respectively. The steps for preparing component B adhesive include: baking the filler in an oven at any constant temperature within the range of 100~130℃ for 2~3 hours, then cooling it to 60~80℃; adding silane-terminated liquid polybutadiene, pigment, crosslinking agent, chain extender, and coupling agent to a dynamic mixer and stirring evenly; then adding the filler and stirring evenly; then turning on the vacuum, and after the vacuum degree is greater than or equal to 0.08MPa, closing the valve to keep the system in a closed and vacuum state; heating to any specific temperature within the range of 60~80℃; maintaining the temperature and stirring for 2~3 hours; and finally cooling the material to room temperature to obtain component B adhesive. During the preparation of component B adhesive, the stirring process maintains the main unit frequency and dispersion frequency at 10~30Hz.

3. A potting compound for photovoltaic inverters, characterized in that, The invention includes a two-component condensation-type silicone potting compound composition as described in claim 1.

4. A potting compound for a photovoltaic optimizer, characterized in that, The invention includes a two-component condensation-type silicone potting compound composition as described in claim 1.

5. A potting compound for high-power electronic appliances and components, characterized in that, The invention includes a two-component condensation-type silicone potting compound composition as described in claim 1.

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