Silicon gel for insulation encapsulation and its preparation method and application

Abstract

The present application relates to a kind of silicon gel for insulation encapsulation and its preparation method and application, it is related to the field of polymer composition, the silicon gel for insulation encapsulation includes the following raw materials: vinyl silicone oil, hydrogen-containing silicone oil, catalyst, inhibitor and the compound shown in formula I.The present application mainly by introducing the compound shown in formula I with large band gap characteristics and high electron affinity, utilize the silane addition reaction of contained vinyl group on the side chain of silicon gel and further by controlling the molar amount of use of silicon vinyl and silicon hydrogen group, the functional modification of the side chain of silicon gel is realized, it can effectively capture the electron injected and excited in silicon gel, and can build a deep trap level, effectively prevent the escape of trapped electron, reduce the carrier concentration and mobility in material interior, so as to improve the insulation performance of silicon gel, can satisfy the use requirement of IGBT module encapsulation.

Description

Technical Field

[0001] This invention relates to the field of polymer compositions, and more particularly to a silicone gel for insulating encapsulation, its preparation method, and its application. Background Technology

[0002] Insulated-gate bipolar transistors (IGBTs), as core power devices in modern power electronics technology, play a crucial role in numerous fields such as new energy vehicles, smart grids, rail transportation, and industrial frequency conversion. IGBT modules, as an integrated packaged form of IGBTs, directly determine the operational efficiency and safety of the entire power electronic system through their stability and reliability. The packaging material, as a vital component of the IGBT module, plays a crucial role in protecting the internal chips, providing electrical insulation, heat dissipation, and withstanding mechanical stress.

[0003] Among numerous encapsulation materials, silicone gel has become one of the most widely used materials in the IGBT module encapsulation field due to its unique performance advantages, such as good flexibility, excellent high and low temperature resistance, and good chemical stability. However, with the continuous development of power electronics technology, IGBT modules are constantly moving towards higher power density, higher switching frequency, and higher operating voltage, which places more stringent requirements on the performance of encapsulating silicone gel. Under high voltage and high frequency operating conditions, a large number of electron injection and excitation phenomena occur inside the silicone gel. During the migration of these excited electrons inside the silicone gel, local electric field concentration can easily occur, leading to faults such as insulation breakdown, which seriously affects the reliability and service life of the IGBT module. Summary of the Invention

[0004] To address the above problems, this invention provides a silicone gel for insulating encapsulation, its preparation method, and its application.

[0005] In a first aspect, the present invention provides a silicone gel for insulating encapsulation, comprising the following raw materials: vinyl silicone oil, hydrogen-containing silicone oil, catalyst, inhibitor and compound shown in Formula I; The molar ratio of vinyl groups in the vinyl silicone oil to hydroxyl groups in the hydrogen-containing silicone oil is (1.8-2.5):1; Equation I: R is selected from at least one of ester group, carbonyl group and fluorine-containing group.

[0006] Furthermore, the compound represented by Formula I includes at least one of the following compounds: compound 1, compound 2, and compound 3: Compound 1: ; Compound 2: ; Compound 3: .

[0007] Furthermore, the molar ratio of the vinyl silicone oil to the hydroxyl groups in the hydrogen-containing silicone oil is 2:1.

[0008] Furthermore, the insulating encapsulation silicone gel comprises the following raw materials in parts by weight: 80 to 100 parts of the vinyl silicone oil, 5 to 7 parts of the hydrogen-containing silicone oil, 0.1 to 1 part of the compound of Formula I, 0.05 to 0.2 parts of the catalyst, and 0.001 to 0.03 parts of the inhibitor.

[0009] Furthermore, the vinyl silicone oil includes a double-ended vinyl silicone oil; The dual-terminated vinyl silicone oil satisfies at least one of the following (a) and (b): (a) The vinyl ester content in the dual-terminated vinyl silicone oil is 0.08 mmol / g to 0.15 mmol / g; (b) The viscosity of the dual-terminated vinyl silicone oil is 900 cst-1100 cst.

[0010] Furthermore, the hydrogen-containing silicone oil includes side-hydrogen-containing silicone oil; The hydrogen-containing silicone oil on the side satisfies at least one of the following (a) and (b): (a) The hydrogen content in the hydrogen-containing silicone oil is 0.8 mmol / g to 1.0 mmol / g; (b) The viscosity of the hydrogen-containing silicone oil is 90 cst-110 cst.

[0011] Furthermore, the catalyst comprises a Pt catalyst, which includes at least one of a Speier catalyst and a Karstedt catalyst.

[0012] Furthermore, the inhibitor comprises an ester compound, which includes at least one of maleate, fumarate, and phosphite.

[0013] Secondly, based on the same inventive concept, the present invention provides a method for preparing the insulating encapsulating silicone gel described in the first aspect, comprising the following steps: The compound shown in Formula I was added to an organic solvent and stirred to obtain a solution of the compound shown in Formula I. Vinyl silicone oil, catalyst, inhibitor and the compound solution shown in Formula I are stirred and then degassed to obtain the base adhesive; The base adhesive and hydrogen-containing silicone oil are stirred, followed by degassing and solvent removal treatments to obtain the silicone gel for insulating encapsulation.

[0014] Thirdly, based on the same inventive concept, the present invention provides the application of the insulating encapsulation silicone gel described in the first aspect or the insulating encapsulation silicone gel prepared by the preparation method described in the second aspect in the encapsulation of IGBT modules.

[0015] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art: This invention provides a silicone gel for insulating encapsulation, its preparation method, and its application. The invention primarily involves introducing a compound of Formula I, which possesses a large band gap and high electron affinity. The vinyl groups contained in this compound undergo a silane addition reaction on the side chains of the silicone gel. Furthermore, by controlling the molar amounts of silyl vinyl and silane hydrogen groups, the functional modification of the silicone gel side chains is achieved. This modification enables the gel to effectively trap electrons injected and excited within the silicone gel and construct a deep trap energy level, effectively preventing the escape of trapped electrons. This reduces the carrier concentration and mobility within the material, thereby improving the insulating properties of the silicone gel and meeting the requirements for IGBT module encapsulation. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The thermogravimetric analysis curves of Examples 1, 2, and 3 and Comparative Example 1 in this invention are shown.

[0019] Figure 2 The images show the XRD curves of Examples 1, 2, and 3 and Comparative Example 1 in this invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. Specifically: Compound 1 in Formula I can be prepared by the following method: adding an organic solvent solution containing acetic anhydride dropwise to an organic solvent solution of N-hydroxy-5-norbornene-2,3-dicarboxyimide, adding an organic base catalyst at room temperature, adding the reaction mixture dropwise to excess water, and filtering to obtain the target compound.

[0022] Compound 2 in Formula I can be prepared by the following method: an organic solvent solution of acetyl chloride is added dropwise to an organic solvent solution of 5-norbornene-2,3-dicarboxyimide, and an organic base catalyst is added at room temperature. After the reaction is completed, the solvent is removed under reduced pressure, the solid is dissolved in another solvent, and the mixture is then added dropwise to excess water and filtered to obtain the target compound.

[0023] Compound 3 in Formula I can be prepared by the following method: an organic solvent solution of 2,2,2-trifluoroethylamine is added dropwise to an organic solvent solution of norbornene ediol, an organic base catalyst is added at room temperature, and the reaction is carried out at 80°C. After cooling, the reaction mixture is added dropwise to excess water and filtered to obtain the target compound.

[0024] Furthermore, unless otherwise specified or explained, the operational steps involved in this invention can be performed according to the processes and parameters disclosed in the prior art. Specifically: The preparation method of silicone gel for insulating encapsulation may include the following steps: Step S1: Add the compound shown in Formula I to ethyl acetate, stir to dissolve, and mix for 3-10 min to obtain a solution of the compound shown in Formula I.

[0025] Step S2: Add catalyst and inhibitor to vinyl silicone oil, stir evenly, and then mix with the compound solution shown in Formula I. The mixing time is 3-10 min. Degas the mixture in a vacuum machine to obtain the base adhesive.

[0026] Step S3: Mix the base adhesive with hydrogen-containing silicone oil for 5-15 minutes, degas the mixture in a vacuum machine, heat it to 50-90℃ to remove the solvent, and cure it to obtain silicone gel for insulating encapsulation.

[0027] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0028] Example 1 This example provides a silicone gel for insulating encapsulation, which, by weight parts, comprises the following raw materials: 94 parts of vinyl silicone oil, 5.585 parts of hydrogen-containing silicone oil, 0.3 parts of compound 1, 0.1 parts of catalyst, and 0.015 parts of inhibitor; Among them, the vinyl silicone oil is a double-ended vinyl silicone oil with a vinyl silicone content of 0.11 mmol / g and a viscosity of 1000 cst. It was purchased from Ambia Specialty Silicones (Nantong) Co., Ltd., and the product model is VS1000. The hydrogen-containing silicone oil is a side-hydrogen-containing silicone oil with a hydrogen content of 0.95 mmol / g and a viscosity of 100 cst. It was purchased from Ambia Specialty Silicones (Nantong) Co., Ltd., and the product model is XL1B. The molar ratio of vinyl groups in the vinyl silicone oil to hydroxyl groups in the hydrogen-containing silicone oil is 2:1. Compound 1: ; The catalyst is a platinum catalyst, specifically a Speier catalyst; The inhibitor is maleate ester.

[0029] The preparation method of the above-mentioned insulating encapsulation silicone gel includes the following steps: Step S1: Add compound 1 to ethyl acetate, stir to dissolve, and mix for 5 minutes to obtain a solution.

[0030] Step S2: Add catalyst and inhibitor to vinyl silicone oil, stir evenly, then mix with solution for 5 minutes, and degas in a vacuum machine to obtain base adhesive.

[0031] Step S3: Mix the base adhesive with hydrogen-containing silicone oil for 10 minutes, degas in a vacuum machine, heat to 70°C to remove solvent, and cure to obtain silicone gel for insulating encapsulation.

[0032] Example 2 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 1 only in that: (1) Replace compound 1 with compound 2 ( ).

[0033] Example 3 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 1 only in that: (1) Replace compound 1 with compound 3 ( ).

[0034] Example 4 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 1 only in that: (1) The insulating encapsulation silicone gel comprises the following raw materials in parts by weight: 93.814 parts of the vinyl silicone oil, 6.035 parts of the hydrogen-containing silicone oil, 0.1 parts of the compound 1, 0.05 parts of the catalyst and 0.001 parts of the inhibitor; (2) The molar ratio of the vinyl silicone oil to the silane group in the hydrogen-containing silicone oil is 1.8:1.

[0035] Example 5 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 1 only in that: (1) The insulating encapsulation silicone gel comprises the following raw materials in parts by weight: 94.4 parts of the vinyl silicone oil, 4.37 parts of the hydrogen-containing silicone oil, 1 part of the compound 1, 0.2 parts of the catalyst and 0.03 parts of the inhibitor; (2) The molar ratio of the vinyl silicone oil to the silane group in the hydrogen-containing silicone oil is 2.5:1.

[0036] Comparative Example 1 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 4 only in that: (1) No compound 1 was added.

[0037] Comparative Example 2 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 4 only in that: (1) Replace compound 1 with .

[0038] Comparative Example 3 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 4 only in that: (1) The molar ratio of the vinyl silicone oil to the silane group in the hydrogen-containing silicone oil is 1:1 (specifically: the mass fraction of the vinyl silicone oil is adjusted to 89.487 parts and the mass fraction of the hydrogen-containing silicone oil is adjusted to 10.362 parts).

[0039] Comparative Example 4 This example provides a silicone gel for insulating encapsulation and its preparation method, which differs from Example 4 only in that: (1) The molar ratio of vinyl silicone oil in the vinyl silicone oil to hydroxyl silicone oil in the hydrogen-containing silicone oil is 3:1 (specifically: the mass fraction of the vinyl silicone oil is adjusted to 96.137 parts and the mass fraction of the hydrogen-containing silicone oil is adjusted to 3.712 parts).

[0040] Test Example 1 This example measures the DC breakdown field strength and resistivity at room temperature of the silicone gels obtained in the above embodiments and comparative examples. The test results are shown in Table 1 below.

[0041] Table 1 Electrical insulation performance of the above embodiments and comparative examples As shown in Table 1, compared with Comparative Examples 1-3, the silicone gel provided in this embodiment of the invention exhibits significantly improved breakdown strength and resistivity, indicating superior insulation performance. This demonstrates that the present invention, primarily by introducing a compound of Formula I with a specific structure and further controlling the molar amounts of silyl vinyl and silane groups, can significantly improve the insulation performance of the silicone gel, meeting the requirements for IGBT module packaging.

[0042] Test Example 2 In this example, thermogravimetric analysis and XRD characterization were performed on the silica gels provided in Examples 1-3 and Comparative Example 1. The test results are as follows: Figure 1 and Figure 2 As shown.

[0043] Depend on Figure 1 It can be seen that the initial decomposition temperature of each embodiment is slightly higher than that of Comparative Example 1, indicating that grafting the compound shown in Formula I into the silica gel enhances the thermal stability of the silica gel. However, since the actual grafting content is small, the effect on the thermal stability of the silica gel is relatively small.

[0044] Depend on Figure 2 It can be seen that the XRD diffraction peak positions of Examples 1-3 and Comparative Example 1 are basically the same, indicating that grafting the compound shown in Formula I into the silica gel has almost no effect on the interchain spacing of the silica gel, and the silica gel skeleton is not destroyed.

[0045] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0046] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A silicone gel for insulating encapsulation, characterized in that, Including the following raw materials: Vinyl silicone oil, hydrogen-containing silicone oil, catalyst, inhibitor and compound of formula I; The molar ratio of vinyl groups in the vinyl silicone oil to hydroxyl groups in the hydrogen-containing silicone oil is (1.8-2.5):1; Equation I: R is selected from at least one of ester group, carbonyl group and fluorine-containing group.

2. The silicone gel for insulating encapsulation according to claim 1, characterized in that, The compound represented by Formula I includes at least one of the following compounds: compound 1, compound 2, and compound 3: Compound 1: ; Compound 2: ; Compound 3: .

3. The silicone gel for insulating encapsulation according to claim 1, characterized in that, The molar ratio of the vinyl silicone oil to the hydroxyl groups in the hydrogen-containing silicone oil is 2:

1.

4. The silicone gel for insulating encapsulation according to claim 1, characterized in that, The insulating encapsulation silicone gel comprises the following raw materials in parts by weight: 80 to 100 parts of the vinyl silicone oil, 5 to 7 parts of the hydrogen-containing silicone oil, 0.1 to 1 part of the compound of Formula I, 0.05 to 0.2 parts of the catalyst, and 0.001 to 0.03 parts of the inhibitor.

5. The silicone gel for insulating encapsulation according to claim 4, characterized in that, The vinyl silicone oil includes double-ended vinyl silicone oil; The dual-terminated vinyl silicone oil satisfies at least one of the following (a) and (b): (a) The vinyl ester content in the dual-terminated vinyl silicone oil is 0.08 mmol / g to 0.15 mmol / g; (b) The viscosity of the dual-terminated vinyl silicone oil is 900 cst-1100 cst.

6. The silicone gel for insulating encapsulation according to claim 4, characterized in that, The hydrogen-containing silicone oil includes side-hydrogen-containing silicone oil; The hydrogen-containing silicone oil on the side satisfies at least one of the following (a) and (b): (a) The hydrogen content in the hydrogen-containing silicone oil is 0.8 mmol / g to 1.0 mmol / g; (b) The viscosity of the hydrogen-containing silicone oil is 90 cst-110 cst.

7. The silicone gel for insulating encapsulation according to claim 4, characterized in that, The catalyst includes a Pt catalyst, which includes at least one of a Speier catalyst and a Karstedt catalyst.

8. The silicone gel for insulating encapsulation according to claim 4, characterized in that, The inhibitor comprises ester compounds, including at least one of maleate, fumarate, and phosphite.

9. A method for preparing the insulating encapsulating silicone gel according to any one of claims 1-8, characterized in that, Includes the following steps: The compound shown in Formula I was added to an organic solvent and stirred to obtain a solution of the compound shown in Formula I. Vinyl silicone oil, catalyst, inhibitor and the compound solution shown in Formula I are stirred and then degassed to obtain the base adhesive; The base adhesive and hydrogen-containing silicone oil are stirred, followed by degassing and solvent removal treatments to obtain the silicone gel for insulating encapsulation.

10. The application of the insulating encapsulation silicone gel according to any one of claims 1-8 or the insulating encapsulation silicone gel prepared by the preparation method according to claim 9 in the encapsulation of IGBT modules.

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