Single-component dealcoholized pouring sealant as well as preparation method and application thereof

Abstract

The invention provides a single-component dealcoholized pouring sealant as well as a preparation method and application thereof, and the single-component dealcoholized pouring sealant is prepared from the following components in parts by weight: 31 to 45 parts of alpha, omega-dihydroxy polydimethylsiloxane, 48 to 64 parts of flame-retardant filler, 0.35 to 0.6 part of powder treating agent N, 0.05 to 0.3 part of powder treating agent T, 0.5 to 2 parts of anti-settling agent, 1 to 5 parts of cross-linking agent, 0.1 to 1 part of coupling agent and 1 to 3 parts of catalyst. The powder treating agent N has a structure as shown in a formula I; the powder treating agent T is selected from titanate compounds. According to the present invention, the single-component dealcoholization type pouring sealant has characteristics of suitable viscosity, excellent damp-heat aging resistance, excellent sedimentation resistance, high heat conductivity coefficient, good mechanical property, high flame retardation grade, and excellent adhesion to different substrates.

Description

Technical Field

[0001] This invention belongs to the field of organosilicon polymer materials technology, specifically relating to a single-component de-alcoholized potting compound, its preparation method, and its application. Background Technology

[0002] As an important branch of organosilicon polymer materials, dealcoholized silicone rubber plays a crucial role in various industrial fields due to its unique curing mechanism and excellent comprehensive performance. During the curing process, it releases small-molecule alcohol byproducts such as ethanol and methanol. Compared with traditional deacidification (releasing corrosive acids) or deoxime (releasing toxic ketone oximes) systems, it exhibits significant environmental friendliness and material compatibility. Therefore, dealcoholized silicone rubber is increasingly being applied in applications with stringent material compatibility requirements, such as precision electronic components, automotive electronics, and smart terminals.

[0003] With the booming development of my country's high-end manufacturing industry, the use of precision electronic components has exploded. To ensure the continuous and stable operation of these components, effective protection measures have become crucial. Potting technology, as a widely adopted protection method, is playing an irreplaceable role. Potting can strengthen the overall integrity of electronic devices, improving their resistance to external shocks and vibrations; it can improve the internal insulation performance of electronic components, facilitating the miniaturization and weight reduction of devices; it can prevent direct exposure of components and circuits, improving the waterproof and moisture-proof performance of devices, thereby enhancing their performance and stability.

[0004] Currently, addition-type potting compounds are the most widely used silicone potting materials, but their adhesion to the substrate is very weak or almost non-existent, making them unsuitable for applications requiring a certain level of adhesion. Furthermore, most existing dealcohol-based potting compounds cannot achieve the UL94-V0 flame retardant rating, and their resistance to damp heat aging and sedimentation needs further improvement, limiting their application areas.

[0005] Therefore, developing a potting compound with suitable viscosity, excellent resistance to damp heat aging, excellent anti-settling properties, high thermal conductivity, good mechanical properties, high flame retardancy, and excellent adhesion to different substrates is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a one-component dealcoholized potting compound, its preparation method, and its applications. The one-component dealcoholized potting compound exhibits moderate viscosity, excellent resistance to damp heat aging, superior anti-settling properties, and excellent adhesion to various substrates. Furthermore, it possesses high thermal conductivity, good mechanical properties, and a high flame retardant rating, thus meeting the high-performance requirements of precision electronic components for potting compounds.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a one-component de-alcoholized potting compound, comprising, by weight, 31-45 parts α,ω-dihydroxypolydimethylsiloxane, 48-64 parts flame-retardant filler, 0.35-0.6 parts powder treatment agent N, 0.05-0.3 parts powder treatment agent T, 0.5-2 parts anti-settling agent, 1-5 parts crosslinking agent, 0.1-1 parts coupling agent, and 1-3 parts catalyst; the flame-retardant filler comprises first aluminum hydroxide, second aluminum hydroxide, and third aluminum hydroxide, wherein the average particle size of the first aluminum hydroxide, second aluminum hydroxide, and third aluminum hydroxide is different; the powder treatment agent N has the structure shown in Formula I; Formula I; in Formula I, R1 is selected from any one of C1~C6 straight-chain or branched alkyl, C2~C6 alkenyl, and C6~C16 aryl; R2 may be the same or different, each independently selected from C1~C6 straight-chain or branched alkyl; n is selected from an integer from 2 to 15; the powder treatment agent T is selected from titanate compounds; the coupling agent includes epoxy silane coupling agents and amino silane coupling agents.

[0009] In this invention, by adding specific types of powder treatment agents N and T, the powder can be surface-treated, improving the compatibility and dispersibility of the powder (especially flame-retardant fillers) in the system, reducing the viscosity of the product, and improving its flowability. Secondly, the introduction of long molecular chains and the formation of hydrogen bonds between the polar groups in the treatment agents and the polar structures in the system help improve the anti-settling performance during storage. Thirdly, urea groups (-NH-CO-NH-) can improve the product's resistance to damp heat and its adhesion to the substrate. The combination of powder treatment agent N and powder treatment agent T has a synergistic effect, which is beneficial to further improve the product's resistance to damp heat. In addition, powder treatment agent T can synergistically improve the flame-retardant performance of the product with flame-retardant fillers.

[0010] Using flame-retardant fillers with different average particle sizes can further improve the product's thermal conductivity, anti-settling properties, and resistance to damp heat aging. Further compounding with anti-settling agents can provide a certain supporting effect for the flame-retardant fillers, thereby further improving the product's anti-settling properties.

[0011] Using coupling agents with specific compositions can improve the product's resistance to damp heat aging and have a synergistic effect on the adhesion performance after damp heat aging.

[0012] In summary, this invention uses specific types of powder treatment agents N and T, along with flame-retardant fillers, α,ω-dihydroxypolydimethylsiloxane, anti-settling agents, crosslinking agents, and coupling agents of specific compositions, in specific amounts to create a single-component de-alcoholized potting compound with moderate viscosity, excellent resistance to damp heat aging, anti-settling properties, and adhesion to different substrates. Furthermore, it possesses high thermal conductivity, good mechanical properties, and a high flame-retardant rating, thus meeting the high-performance requirements of precision electronic components for potting compounds.

[0013] In this invention, the single-component de-alcoholized potting compound comprises 31 to 45 parts of α,ω-dihydroxypolydimethylsiloxane, for example, 31.5 parts, 32 parts, 32.5 parts, 33 parts, 33.5 parts, 34 parts, 34.5 parts, 35 parts, 35.5 parts, 36 parts, 36.5 parts, 37 parts, 37.5 parts, 38 parts, 38.5 parts, 39 parts, 39.5 parts, 40 parts, 40.5 parts, 41 parts, 41.5 parts, 42 parts, 42.5 parts, 43 parts, 43.5 parts, 44 parts, 44.5 parts, etc.

[0014] In this invention, 48 to 64 parts of flame-retardant filler can be, for example, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, etc.

[0015] In this invention, 0.35 to 0.6 parts of powder treatment agent N can be, for example, 0.36 parts, 0.38 parts, 0.4 parts, 0.42 parts, 0.44 parts, 0.46 parts, 0.48 parts, 0.5 parts, 0.52 parts, 0.54 parts, 0.56 parts, 0.58 parts, etc.

[0016] In this invention, 0.05 to 0.3 parts of powder treatment agent T can be, for example, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.2 parts, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, etc.

[0017] In this invention, 0.5 to 2 parts of anti-settling agent can be, for example, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, etc.

[0018] In this invention, 1 to 5 parts of crosslinking agent can be, for example, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, etc.

[0019] In this invention, 0.1 to 1 part of coupling agent, for example, can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, etc.

[0020] In this invention, 1 to 3 parts of catalyst, for example, can be 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, etc.

[0021] In this invention, the C1-C6 straight-chain or branched alkyl group can be, for example, a C2, C3, C4, or C5 straight-chain or branched alkyl group, including but not limited to methyl, ethyl, isopropyl, n-propyl, n-butyl, n-hexyl, etc.

[0022] In this invention, the C2~C6 alkenyl group can be, for example, a C2, C3, C4, or C5 alkenyl group, and exemplary includes, but is not limited to, vinyl, propenyl, butenyl, and hexenyl groups.

[0023] In this invention, the C6~C16 aryl group can be, for example, C8, C10, C12, C14 aryl groups; exemplary, it includes but is not limited to phenyl, naphthyl, biphenyl, phenanthryl, fluorene, etc.

[0024] In this invention, n is selected from integers from 2 to 15, such as 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, etc.

[0025] Preferably, the kinematic viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 500~5000 mPa·s, for example, it can be 600 mPa·s, 800 mPa·s, 1000 mPa·s, 1200 mPa·s, 1500 mPa·s, 1800 mPa·s, 2000 mPa·s, 2200 mPa·s, 2500 mPa·s, 2800 mPa·s, 3000 mPa·s, 3200 mPa·s, 3500 mPa·s, 3800 mPa·s, 4000 mPa·s, 4200 mPa·s, 4500 mPa·s, 4800 mPa·s, etc.

[0026] Preferably, by weight, the α,ω-dihydroxy polydimethylsiloxane comprises 8 to 28 parts (e.g., 10, 12, 14, 16, 18, 20, 22, 24, 26, etc.) of first α,ω-dihydroxy polydimethylsiloxane and 6 to 30 parts (e.g., 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, etc.) of second α,ω-dihydroxy polydimethylsiloxane; the kinematic viscosity of the second α,ω-dihydroxy polydimethylsiloxane is greater than that of the first α,ω-dihydroxy polydimethylsiloxane.

[0027] Preferably, the kinematic viscosity of the first α,ω-dihydroxypolydimethylsiloxane at 25°C is <2500 mPa·s, more preferably <2000 mPa·s, and even more preferably 500-1500 mPa·s.

[0028] Preferably, the kinematic viscosity of the second α,ω-dihydroxypolydimethylsiloxane at 25°C is ≥2500 mPa·s, more preferably ≥3000 mPa·s, and even more preferably 4000-5000 mPa·s.

[0029] In this invention, α,ω-dihydroxy polydimethylsiloxanes of different viscosities are used, which allows for flexible adjustment of the ratio of high- and low-viscosity base adhesives. This maintains good flowability without excessively sacrificing elongation performance. At the same time, the high-viscosity adhesive provides long molecular chains as a backbone, while the low-viscosity adhesive has short chains that enhance crosslinking density, which is more conducive to obtaining products with balanced mechanical properties such as tensile strength and elongation at break.

[0030] Preferably, the average particle size of the flame-retardant filler is 5~30μm, for example, it can be 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, 22μm, 24μm, 26μm, 28μm, etc.

[0031] Preferably, by weight, the flame-retardant filler comprises 30-45 parts (e.g., 32, 34, 36, 38, 40, 42, 44, etc.) of aluminum hydroxide first, 10-20 parts (e.g., 11, 12, 13, 14, 15, 16, 17, 18, 19, etc.) of aluminum hydroxide second, and 2-7 parts (e.g., 2.2, 2.5, 2.8, 3, 3.2, 3.5) of aluminum hydroxide second. The first aluminum hydroxide has an average particle size > 20 μm, preferably 25-30 μm; the second aluminum hydroxide has an average particle size of 10-20 μm, preferably 13-17 μm; and the third aluminum hydroxide has an average particle size < 10 μm, preferably 5-8 μm.

[0032] Preferably, R1 is selected from any one of methyl, vinyl, and phenyl; R2 is independently selected from methyl and / or ethyl.

[0033] In this invention, R1 is more preferably C6~C16 aryl, which provides greater steric hindrance and is beneficial to the stability of the powder in the system; it is also beneficial to further improve the resistance to humid heat aging and the anti-settling properties.

[0034] Preferably, the powder treatment agent N is selected from at least one of the following compounds.

[0035] , , , , .

[0036] In this invention, the powder treatment agent N can be prepared using conventional methods in the art, such as by reacting amine compounds and siloxane compounds containing isocyanate groups as raw materials with amino groups.

[0037] Preferably, the powder treatment agent T comprises isopropyl triisostearate titanate and / or isopropyl tris(dioctyl pyrophosphate) titanate.

[0038] Preferably, the anti-settling agent comprises nano-calcium carbonate.

[0039] In this invention, the average particle size of the nano-calcium carbonate is 50~150nm, for example, it can be 60 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 140 nm, etc.

[0040] Preferably, the crosslinking agent includes silane compounds and / or silicate ester compounds.

[0041] In this invention, the crosslinking agent comprises 1 to 1.5 parts by weight of a silane compound and 1 to 1.5 parts by weight of a silicate ester compound.

[0042] Preferably, the silane compound includes at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and phenyltrimethoxysilane.

[0043] Preferably, the silicate ester compound includes at least one of methyl orthosilicate and ethyl orthosilicate.

[0044] Preferably, the molar ratio of the epoxy silane coupling agent to the amino silane coupling agent is (0.8~1.2):1, for example, it can be 0.85:1, 0.9:1, 0.95:1, 1:1, 1.05:1, 1.1:1, 1.15:1, etc.

[0045] Preferably, the epoxy silane coupling agent includes at least one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) and 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane.

[0046] Preferably, the aminosilane coupling agent includes at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane.

[0047] Preferably, the catalyst comprises a titanium complex.

[0048] In a second aspect, the present invention provides a method for preparing a single-component de-alcoholized potting compound according to the first aspect, the method comprising the following steps:

[0049] The single-component de-alcoholized potting compound is obtained by mixing α,ω-dihydroxypolydimethylsiloxane, flame retardant filler, powder treatment agent N, powder treatment agent T, anti-settling agent, crosslinking agent, coupling agent and catalyst.

[0050] Preferably, the mixing method includes the following steps:

[0051] (1) Premix α,ω-dihydroxy polydimethylsiloxane, flame retardant filler, anti-settling agent and powder treatment agent N, and then add powder treatment agent T to it for mixing to obtain mixture A;

[0052] (2) Mix the mixture A with a crosslinking agent to obtain mixture B;

[0053] (3) Mix the mixture B with the coupling agent and the catalyst to obtain the single-component de-alcoholized potting compound.

[0054] Preferably, step (1) includes: stirring α,ω-dihydroxypolydimethylsiloxane, flame retardant filler, anti-settling agent and powder treatment agent N at room temperature and a vacuum of 0.08~0.1MPa for 5~25 min (e.g., 10 min, 15 min, 20 min, etc.). After stirring at 130~160℃ (e.g., 135℃, 140℃, 145℃, 150℃, 155℃, etc.) for 0.3~1h (e.g., 0.4h, 0.6h, 0.8h, etc.), the temperature is then lowered to 100~130℃ (e.g., 105℃, 110℃, 115℃, 120℃, 125℃, etc.), powder treatment agent T is added, and the mixture is stirred at 100~130℃ (e.g., 105℃, 110℃, 115℃, 120℃, 125℃, etc.) and a vacuum degree of 0.08~0.1MPa for 1~3h (e.g., 1.2h, 1.5h, 1.8h, 2h, 2.2h, 2.5h, 2.8h, etc.) to obtain mixture A.

[0055] Preferably, the vacuum degree of mixing in steps (2) and (3) is 0.08~0.1MPa and the time is 0.1~2h (for example, it can be 0.5h, 1h, 1.5h, etc.).

[0056] Thirdly, the present invention provides an application of the single-component de-alcoholized potting compound according to the first aspect in precision electronic components.

[0057] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] The single-component de-alcoholized potting compound provided by this invention uses specific types of powder treatment agents N and T, along with flame-retardant fillers, α,ω-dihydroxypolydimethylsiloxane, anti-settling agents, crosslinking agents, and coupling agents of specific compositions, in specific amounts to achieve a single-component de-alcoholized potting compound with moderate viscosity, excellent resistance to damp heat aging, anti-settling properties, and adhesion to different substrates. It also possesses high thermal conductivity, good mechanical properties, and a high flame retardant rating, meeting the high-performance requirements of precision electronic components for potting compounds. Detailed Implementation

[0060] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0061] All materials used in this invention can be purchased commercially or prepared using conventional methods. Unless otherwise specified, the materials used in this invention are as follows.

[0062] Epoxysilane coupling agent 1: 3-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0063] Epoxysilane coupling agent 2: 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane.

[0064] 1: 3-Aminopropyltrimethoxysilane coupling agent.

[0065] Aminosilane coupling agent 2: 3-aminopropyltriethoxysilane.

[0066] Aminosilane coupling agent 3: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0067] Aminosilane coupling agent 4: N-(2-aminoethyl)-3-aminopropyltriethoxysilane.

[0068] Powder treatment agent T

[0069] T1: Isopropyl triisostearate titanate.

[0070] T2: Isopropyl tris(dioctylpyrophosphoryloxy)titanate.

[0071] Powder treatment agent N

[0072] Preparation method of N1:

[0073] Under the protection of dry nitrogen, 3-isocyanate-propyltrimethoxysilane and n-undecylamine in a molar ratio of 1.05:1, along with dehydrated toluene of the same mass as the reactants (i.e., 3-isocyanate-propyltrimethoxysilane and n-undecylamine), are added to the reactor. The mixture is stirred and heated to 80°C, and the reaction is maintained at this temperature for 8 hours under the protection of dry nitrogen. Toluene and unreacted raw materials are removed by vacuum distillation to obtain powder treatment agent N1.

[0074] The preparation methods of powder treatment agents N2-N5 differ from those of powder treatment agent N1 only in that n-undecylamine is replaced with the corresponding amine compound raw material. The other raw materials, dosages, and preparation methods are the same as those of powder treatment agent N1.

[0075] N1: .

[0076] N2: .

[0077] N3: .

[0078] N4: .

[0079] N5: .

[0080] Example 1

[0081] This embodiment provides a one-component de-alcoholized potting compound, which, by weight, comprises 24 parts of α,ω-dihydroxypolydimethylsiloxane with a kinematic viscosity of 1500 mPa•s, 14 parts of α,ω-dihydroxypolydimethylsiloxane with a kinematic viscosity of 5000 mPa•s, 33.6 parts of aluminum hydroxide with an average particle size of 30 μm, 16.8 parts of aluminum hydroxide with an average particle size of 15 μm, 5.6 parts of aluminum hydroxide with an average particle size of 5 μm, 0.6 parts of nano-calcium carbonate with an average particle size of 90 nm, and 0.4 parts of powder treatment agent N (… ), 0.3 parts powder treatment agent T (triisostearate titanate isopropyl), 1.5 parts methyltrimethoxysilane, 1 part methyl orthosilicate, 0.19 parts 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.21 parts 3-aminopropyltriethoxysilane and 1.5 parts titanium complex Tyzor 726.

[0082] This embodiment provides a method for preparing a one-component dealcoholized potting compound, specifically including the following steps:

[0083] (1) According to the formula, α,ω-dihydroxypolydimethylsiloxane with a kinematic viscosity of 1500 mPa•s, α,ω-dihydroxypolydimethylsiloxane with a kinematic viscosity of 5000 mPa•s, aluminum hydroxide with an average particle size of 30 μm, aluminum hydroxide with an average particle size of 15 μm, aluminum hydroxide with an average particle size of 5 μm, nano-calcium carbonate with an average particle size of 90 nm, and powder treatment agent N are added to the planetary machine. First, stir for 15 min under a vacuum of 0.08~0.1 MPa, raise the temperature to 150℃, stir for 0.5 h under normal pressure, cool to 120℃, add powder treatment agent T, and continue stirring for 2 h at 120℃ and a vacuum of 0.08~0.1 MPa, and cool to 40-60℃ to obtain mixture A.

[0084] (2) Add methyltrimethoxysilane and methyl orthosilicate to the mixture A, and stir for 0.5 h under a vacuum of 0.08~0.1 MPa to obtain mixture B.

[0085] (3) Add 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-aminopropyltriethoxysilane, and Tyzor 726 to the mixture B, and stir for 0.5 h under a vacuum of 0.08~0.1 MPa to obtain the single-component de-alcoholized potting compound.

[0086] Examples 2-15 and Comparative Examples 1-8 each provide a one-component de-alcoholized potting compound, which differs from Example 1 in that the formulation is different, as shown in Tables 1-3; the preparation methods of the one-component de-alcoholized potting compounds are the same as those of Example 1.

[0087] Unless otherwise specified, the kinematic viscosity in this invention refers to the viscosity at 25°C; unless otherwise specified, the preparation method refers to the viscosity at room temperature and pressure.

[0088] Table 1

[0089]

[0090] Table 2

[0091]

[0092] Table 3

[0093]

[0094] Performance testing

[0095] 1. Surface drying time: Tested according to GB / T 13477.5-2002.

[0096] 2. Viscosity: Tested according to GB / T 2794-2022.

[0097] 3. Hardness: Tested according to GB / T 531.1-2008. The sample was cured for 7 days at 25℃±2℃ / 50%±5%RH before testing.

[0098] 4. Tensile strength and elongation at break: Tested according to GB / T 528-2009. The specimens were cured for 7 days at 25℃±2℃ / 50%±5%RH before testing.

[0099] 5. Thermal conductivity: Tested according to ASTM D5470, the sample was tested after being cured for 7 days at 25℃±2℃ / 50%±5%RH.

[0100] 6. Shear strength: Tested according to GB / T 7124-2008. The samples were cured for 7 days at 25℃±2℃ / 50%±5%RH before testing. Shear strength characterizes the adhesion performance of the one-component de-alcoholized potting compound to different substrates.

[0101] 7. Cohesive failure rate: After shear strength testing, take the substrate sample with relatively less residual adhesive from the two separated substrate samples, and count the area of ​​adhesive remaining on the substrate surface, denoted as S. 残 Then, the cohesive failure rate is calculated using the following formula:

[0102] .

[0103] Where S 粘 This indicates the total bonding area of ​​the adhesive on the substrate sample.

[0104] 8. Resistance to damp heat aging (double 85 / 1000H): The samples were first cured at 25℃±2℃ / 50%±5%RH for 7 days, and then aged at 85℃±3℃ / 85%±3%RH for 1000 hours. The shear strength, cohesive failure rate, tensile strength and elongation at break of different substrates were tested according to the above method.

[0105] 9. Settling Rate: After filling with a commonly used transparent 300ml plastic tube containing sealant, place the tube with the tail facing upwards. After a certain period of time, measure the height of the clear liquid at the top and the total height of the filled sealant. Then calculate the settling rate using the following formula: .

[0106] 10. Flame retardancy rating: Tested according to the vertical method in GB / T 2408-2021. The sample is tested after being cured for 7 days in an environment of 25℃±2℃ / 50%±5%RH.

[0107] The specific test results are shown in Table 4-6.

[0108] Table 4

[0109]

[0110] Table 5

[0111]

[0112] Table 6

[0113]

[0114] As shown in Tables 4-6, the single-component de-alcoholized potting compound provided by the present invention is formulated with specific types of powder treatment agent N and powder treatment agent T, flame retardant filler, α,ω-dihydroxy polydimethylsiloxane, anti-settling agent, crosslinking agent, and coupling agent of a specific composition in specific amounts. This results in a single-component de-alcoholized potting compound with moderate viscosity, excellent resistance to damp heat aging, excellent anti-settling performance, and excellent adhesion to different substrates. At the same time, it also has a high thermal conductivity, good mechanical properties, and a high flame retardant rating, which can meet the high-performance requirements of precision electronic components for potting compounds.

[0115] Comparative Example 1, due to the absence of powder treatment agents N and T in the formulation, had a higher viscosity. Furthermore, the adhesion to all three substrates decreased after double 85 / 1000H, with a settling rate of 9.63% after 6 months. In contrast, the formulation using both powder treatment agents N and T showed significant improvements in the aforementioned properties.

[0116] Comparative Example 2, which uses only large-particle-size aluminum hydroxide, has a lower viscosity and relatively lower thermal conductivity, and its sedimentation rate reaches 8.72% after 6 months. In contrast, the formulation using aluminum hydroxide with different particle sizes can improve the thermal conductivity to some extent and improve the sedimentation. This indicates that the reasonable combination of thermally conductive fillers with different particle sizes helps to improve the thermal conductivity and sedimentation.

[0117] When Comparative Examples 5 and 6 used only aminosilane or epoxysilane as coupling agents, they could not achieve 100% cohesive breakdown rate on all substrates after Double 85 / 1000H. However, the formulations using both coupling agents and both powder treatment agents simultaneously achieved 100% cohesive breakdown rate on all substrates after Double 85 / 1000H. This indicates that the use of the two powder treatment agents is beneficial to improving the product's resistance to damp heat and has a synergistic enhancing effect on the adhesion performance after Double 85.

[0118] Comparative Examples 7 and 8 did not use powder treatment agent N with a specific structure, resulting in poorer anti-settling properties and / or resistance to damp heat aging of the single-component de-alcoholized potting compound.

[0119] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A one-component dealcoholized pouring sealant, characterized by, The single-component dealcoholization type pouring sealant comprises 31-45 parts of α, ω-dihydroxy polydimethylsiloxane, 48-64 parts of flame-retardant filler, 0.35-0.6 parts of powder treating agent N, 0.05-0.3 parts of powder treating agent T, 0.5-2 parts of anti-settling agent, 1-5 parts of crosslinking agent, 0.1-1 part of coupling agent and 1-3 parts of catalyst in terms of weight; The flame-retardant filler comprises first, second and third aluminum hydroxides, and the average particle sizes of the first, second and third aluminum hydroxides are different; The powder treating agent N has a structure shown in Formula I; Formula I; In Formula I, R1 is selected from any one of C1-C6 linear or branched alkyl, C2-C6 alkenyl and C6-C16 aryl; R2 is the same or different, and each is independently selected from C1-C6 linear or branched alkyl; and n is an integer selected from 2-15. The powder treating agent T is selected from titanate compounds; The coupling agent comprises epoxy silane coupling agent and amino silane coupling agent.

2. The one-component dealcoholized pouring sealant according to claim 1, characterized in that, The α, ω-dihydroxy polydimethylsiloxane has a kinematic viscosity of 500-5000 mPa·s at 25°C; Preferably, the α, ω-dihydroxy polydimethylsiloxane comprises 8-28 parts of first α, ω-dihydroxy polydimethylsiloxane and 6-30 parts of second α, ω-dihydroxy polydimethylsiloxane in terms of weight; and the kinematic viscosity of the second α, ω-dihydroxy polydimethylsiloxane is greater than that of the first α, ω-dihydroxy polydimethylsiloxane. Preferably, the first α, ω-dihydroxy polydimethylsiloxane has a kinematic viscosity of < 2500 mPa·s at 25°C. Preferably, the second α, ω-dihydroxy polydimethylsiloxane has a kinematic viscosity of ≥ 2500 mPa·s at 25°C.

3. The one-component dealcoholized pouring sealant according to claim 1 or 2, characterized in that, The average particle size of the flame-retardant filler is 5-30 μm; Preferably, the flame-retardant filler comprises 30-45 parts of first aluminum hydroxide, 10-20 parts of second aluminum hydroxide and 2-7 parts of third aluminum hydroxide in terms of weight; the average particle size of the first aluminum hydroxide is > 20 μm, the average particle size of the second aluminum hydroxide is 10-20 μm, and the average particle size of the third aluminum hydroxide is < 10 μm.

4. The one-component dealcoholized pouring sealant according to any one of claims 1 to 3, characterized in that, R1 is selected from any one of methyl, vinyl and phenyl; and R2 is each independently selected from methyl and / or ethyl; Preferably, the powder treating agent N is selected from at least one of the following compounds: 、 、 、 、 ； Preferably, the powder treating agent T comprises titanium isopropyl triisostearate and / or isopropyl tri(dioctyl pyrophosphato) titanate.

5. The one-component dealcoholized pouring sealant according to any one of claims 1 to 4, characterized in that, The anti-settling agent comprises nano calcium carbonate; Preferably, the crosslinking agent comprises silane compound and / or silicate compound; Preferably, the silane compound comprises at least one of methyl trimethoxysilane, methyl triethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane and phenyl trimethoxysilane. Preferably, the silicate compound comprises at least one of methyl orthosilicate and ethyl orthosilicate.

6. The one-component dealcoholized pouring sealant according to any one of claims 1 to 5, characterized in that, The molar ratio of the epoxy silane coupling agent to the amino silane coupling agent is (0.8-1.2):

1. Preferably, the epoxy silane coupling agent comprises at least one of 3-(2,3-epoxypropoxy)propyl trimethoxysilane, 3-(2,3-epoxypropoxy)propyl methyldimethoxysilane; Preferably, the amino silane coupling agent comprises at least one of 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyl triethoxysilane; Preferably, the catalyst comprises a titanium complex.

7. A method for preparing the one-component dealcoholized pouring sealant according to any one of claims 1 to 6, characterized in that, The preparation method comprises the following steps: The α, ω-dihydroxypolydimethylsiloxane, the flame-retardant filler, the powder treating agent N, the powder treating agent T, the anti-settling agent, the crosslinking agent, the coupling agent and the catalyst are mixed to obtain the single-component dealcoholization type pouring sealant.

8. The preparation method according to claim 7, characterized in that, The mixing method comprises the following steps: (1) The α, ω-dihydroxypolydimethylsiloxane, the flame-retardant filler, the anti-settling agent and the powder treating agent N are premixed, then the powder treating agent T is added and mixed to obtain a mixed material A; (2) The mixed material A is mixed with the crosslinking agent to obtain a mixed material B; (3) The mixed material B is mixed with the coupling agent and the catalyst to obtain the single-component dealcoholization type pouring sealant.

9. The preparation method according to claim 8, characterized in that, Step (1) comprises: stirring the α, ω-dihydroxypolydimethylsiloxane, the flame-retardant filler, the anti-settling agent and the powder treating agent N at room temperature under a vacuum degree of 0.08-0.1 MPa for 5-25 min, then stirring at 130-160 ℃ for 0.3-1 h, then reducing the temperature to 100-130 ℃, adding the powder treating agent T, and stirring at a temperature of 100-130 ℃ under a vacuum degree of 0.08-0.1 MPa for 1-3 h to obtain the mixed material A; Preferably, the vacuum degree of the mixing in step (2) and step (3) is independently 0.08-0.1 MPa, and the time is independently 0.3-1 h.

10. An application of the single-component dealcoholization type pouring sealant according to any one of claims 1-6 in precision electronic components.

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