High-temperature-resistant organic silica gel as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organic silicon materials, in particular to high-temperature-resistant organic silicon gel and a preparation method and application thereof.The high-temperature-resistant organic silicon gel is formed by mixing and curing a component A and a component B. The component A comprises vinyl silicone oil, hydrogen-containing silicone oil, an inhibitor and a cerium-based heat-resistant agent, the component A comprises vinyl silicone oil and hydrogen-containing silicone oil, the component B comprises vinyl silicone oil and a platinum catalyst, and the component A and / or the component B further comprise an organosilicon compound containing a dynamic reversible crosslinking group, so that on the basis of a crosslinking network formed by addition of the vinyl silicone oil and the hydrogen-containing silicone oil under catalysis of the platinum catalyst, the dynamic reversible crosslinking group is obtained. And a dynamic cross-linked network with energy dissipation capability at high temperature is formed in situ. According to the invention, thermal stress is actively dissipated through a dynamic coordination cross-linked network (such as pyridine-zinc bonds), and main chain protection of the cerium-based heat-resistant agent is matched, so that the gel still keeps excellent elasticity after long-term aging at 200 DEG C, the hardening and cracking problems are completely eradicated, and the use limit of the traditional silica gel at 150 DEG C is broken through.

Description

Technical Field

[0001] This invention relates to the field of organosilicon materials technology, specifically to a high-temperature resistant organosilicon gel, its preparation method, and its application. Background Technology

[0002] Transparent silicone gels are widely used in LED packaging, optical devices, and other fields due to their excellent transparency, flexibility, electrical insulation, and weather resistance. Traditional transparent silicone gels are typically based on polydimethylsiloxane, and their long-term operating temperature generally does not exceed 150-180°C. Above this temperature, the material undergoes significant oxidation or degradation, leading to increased hardness, loss of elasticity, decreased transparency, and severe yellowing, thus affecting the performance and lifespan of the encapsulated devices. With technological advancements, many emerging fields are placing more stringent demands on encapsulation materials. For example, high-power LEDs (especially UV LEDs), high-temperature sensors, electronic control units in automotive engine compartments, and aerospace electronic equipment often require materials to operate stably for extended periods in high-temperature environments above 200°C. Therefore, developing a transparent silicone gel that retains the inherent advantages of silicone gels while withstanding extreme high temperatures without performance degradation has significant industrial value and market potential. Most organosilicon gels suffer from drawbacks such as easy hardening at high temperatures (200°C) and limited long-term usability.

[0003] Traditional addition-type silicone gels have the following problems under long-term high-temperature conditions: Poor thermal aging performance: At high temperatures, it will undergo oxidative cross-linking (become brittle and hard) or degradation (become sticky and tacky), resulting in a serious decline in mechanical properties and loss of protection for precision components; High volatility: Low molecular weight siloxane cyclic compounds or unreacted monomers are easily volatilized at high temperatures. The volatiles may condense on nearby precision optical components or circuit boards, causing pollution and short circuit risks. Insufficient toughness: The network structure formed by conventional silicone gel after cross-linking is relatively simple. When subjected to thermal or mechanical stress, cracks are prone to propagate, resulting in low tear strength and easy breakage.

[0004] While existing technologies have attempted to improve heat resistance by adding heat-resistant additives or using partially aryl-containing silicone oils, these often sacrifice the material's transparency, processability, or mechanical properties. For example, adding inorganic fillers can cause the gel to become cloudy and increase its hardness; while simply increasing the crosslinking density can reduce volatiles, it can make the gel brittle. Therefore, developing an organosilicon gel that combines excellent high-temperature resistance, low viscosity, high transparency, and good toughness to meet the needs of high-end industrial applications is of great significance. Summary of the Invention

[0005] The present invention aims to overcome the difficulty in balancing heat resistance, transparency and mechanical properties in existing organosilicon gels. Therefore, it provides a high-temperature resistant organosilicon gel, its preparation method and application to overcome the above-mentioned shortcomings.

[0006] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a high-temperature resistant organosilicon gel, which is formed by mixing and curing a component A and a component B. The component A contains vinyl silicone oil, hydrogen-containing silicone oil, inhibitors, and cerium-based heat-resistant agents. The component B contains vinyl silicone oil and a platinum catalyst. The component A and / or component B further contain organosilicon compounds containing dynamically reversible crosslinking groups, thereby enabling the formation of a dynamic crosslinking network with energy dissipation capability at high temperatures on the basis of a crosslinking network formed by the addition of vinyl silicone oil and hydrogen-containing silicone oil under the catalysis of a platinum catalyst.

[0007] As described in the background section, traditional silicone gels generally suffer from the fatal defect of hardening and cracking when operating at temperatures above 150°C for extended periods. This is because high temperatures accelerate the oxidative degradation and excessive cross-linking of the siloxane backbone: on the one hand, siloxane chain segment breakage leads to material stickiness, and on the other hand, free radical-induced side chain cross-linking makes the material brittle. Existing technologies mainly rely on adding heat-resistant additives (such as cerium compounds) to delay the oxidation process, but their effect is essentially a passive physical shielding, which cannot prevent the propagation of microcracks caused by stress accumulation. More importantly, when the operating temperature exceeds the 200°C threshold, solutions relying solely on antioxidants often fail, and the material will still rapidly harden and crack under the dual pressure of thermo-oxidative aging and mechanical stress. This limitation is particularly prominent in the field of high-power semiconductor packaging, where the thermal stress generated by long-term device operation will continuously tear the packaging material. Traditional silicone gels, lacking an effective energy dissipation mechanism, will inevitably fail as a result.

[0008] Addressing this industry pain point, this application goes beyond passive defense of "delayed degradation" and actively mitigates destructive energy by constructing a "dynamic adaptive network." Its core innovation lies in the groundbreaking design of a triple synergistic mechanism: firstly, it retains the basic antioxidant function of the cerium-based heat-resistant agent, enabling it to continuously capture free radicals to protect the siloxane backbone; secondly, it forms the main cross-linking network through platinum-catalyzed hydrosilylation, providing basic mechanical strength; and most innovatively, it introduces a compound containing dynamically reversible cross-linking groups. This compound remains inert at room temperature, ensuring that the gel mixing viscosity remains within the easily workable range of 300-800 mPa·s without affecting the hydrosilylation curing process. However, when the temperature rises to the working range of 150-250℃, the dynamic cross-linking groups (such as pyridine-metal coordination bonds) are activated, forming reversible connection points in situ between the main network backbone. These dynamic bonds act like intelligent "molecular dampers": when thermal stress causes local deformation, the coordination bonds can reversibly break and absorb energy; after stress release, they can quickly recombine and repair micro-damage. This mechanism fundamentally alters the high-temperature behavior of materials. While traditional silica gels accumulate irreversible damage under stress, this approach converts destructive mechanical energy into reversible intramolecular energy through a continuous cycle of dynamic bond breaking and recombination.

[0009] This synergistic effect of "antioxidant-solidification-energy dissipation" produces technical results far exceeding those of simple superposition. During long-term aging at 200℃, the cerium-based heat resistant agent delays the oxidation of the main chain, maintaining the integrity of the material itself; the main cross-linking network maintains basic elasticity; and the dynamic network undertakes the most critical function of thermal stress buffering. The combined effect of these three factors allows the gel to maintain excellent elastic recovery ability even at extreme temperatures, completely eliminating hardening and cracking. Especially in semiconductor packaging scenarios, the dynamic network's ability to dissipate heat stress directly blocks the initiation of microcracks, solving the packaging failure problem caused by stress concentration in traditional materials. Compared to the comparative example containing only cerium-based heat resistant agent (which embrittles and cracks after 500 hours), the revolutionary improvement shown by this solution under the same conditions essentially stems from a technological leap from "delaying failure" to "fundamental prevention."

[0010] From the perspective of implementation, this breakthrough is attributed to precise molecular design. Integrating dynamic crosslinking groups into organosilicon compounds ensures compatibility with components A and B, while also enabling intelligent temperature-responsive switching through molecular structure control. For example, vinyl silicone oils with pyridine groups in the side chains exhibit a linear thickening effect during room-temperature processing; however, during high-temperature operation, the pyridine groups spontaneously coordinate with metal ions, forming an energy dissipation network that runs throughout the entire system. This "one molecule, two functions" design avoids phase separation or viscosity runaway caused by added additives, ensuring that the material possesses both processability and long-term reliability. More importantly, the activation temperature (150-250℃) of this dynamic network closely matches the operating temperature range of power semiconductors, demonstrating precise innovation tailored to specific application scenarios.

[0011] Therefore, in summary, the technical solution in this application fundamentally reconstructs the material response mechanism under high-temperature conditions through synergistic innovation at the molecular level: with a dynamic reversible cross-linked network as the core, cerium-based antioxidants as the main chain shield, and a hydrosilylation network as the framework support, the three work together to form an organic whole, thereby solving the problem of high-temperature hardening cracking that has plagued the industry for many years. Furthermore, the creative introduction of dynamic bond principles such as coordination chemistry into the silica gel system achieves perfect compatibility with existing processes, thus exhibiting disruptive performance advantages.

[0012] Preferably, the dynamic reversible crosslinking group is a coordination crosslinking group, which is composed of an electron-donating group and a metal ion; The electron-donating group is selected from pyridyl, carboxyl, or amino groups; The metal ions are selected from zinc ions, iron ions, or copper ions.

[0013] This application utilizes the dynamic coordination of electron-donating groups (pyridyl, carboxyl, or amino groups) with specific metal ions (zinc, iron, copper) at high temperatures to endow the material with intelligent energy dissipation capabilities. When thermal stress is applied to the gel, the metal coordination bonds reversibly break to absorb mechanical energy; after the stress is relieved, the coordination bonds rapidly recombine to repair micro-damage, forming a self-protective mechanism similar to a "molecular fuse." This dynamic behavior is essentially complementary to the hydrosilylation network: the addition network provides basic structural support, while the coordination network actively dissipates destructive energy; the two work together to fundamentally prevent the initiation and propagation of microcracks.

[0014] This technical solution offers the following advantages: First, it creatively introduces coordination chemistry principles into high-temperature organosilicon systems. Traditional modification focuses on delaying main-chain oxidation (e.g., adding cerium compounds), while this solution takes a different approach by altering the material failure mode through the reversibility of coordination bonds. Second, it precisely selects specific electron donor combinations with metal ions. Pairings such as pyridyl / zinc ions exhibit ideal thermal responsiveness in the 150-250℃ range, avoiding low-temperature mis-triggers that could affect processing while ensuring rapid establishment of a dynamic network at high temperatures. Such precise matching of temperature windows requires extensive experimental verification. Third, it breaks through the conventional thinking that coordination bonds are only used for room-temperature self-healing. Existing technologies mostly utilize coordination bonds to achieve room-temperature repair, while this solution reverses this by utilizing their high-temperature dissociation characteristics to develop a thermal stress buffer function. This creative shift in application scenario solves the unique thermomechanical failure problem of power semiconductor packaging.

[0015] Preferably, the electron-donating group is derived from vinyl silicone oil whose side chain or end group contains the electron-donating group; The metal ions are derived from metal carboxylates or metal chelates added to component A or component B.

[0016] Preferably, the metal carboxylate or metal chelate is selected from zinc acetylacetonate, iron stearate, copper naphthenate, or sodium iron ethylenediaminetetraacetate.

[0017] Preferably, the amount of vinyl silicone oil containing the electron-donating group in the side chain or end group is 0.5-10 wt% of the vinyl silicone oil. The amount of the metal carboxylate or metal chelate added is 0.01-2 wt% of the vinyl silicone oil.

[0018] Preferably, the vinyl silicone oil includes one or more of the following: terminal vinyl silicone oil, vinyl-terminated diphenyl-dimethyl copolymer silicone oil, side vinyl silicone oil, and silicone oil containing vinyl groups and side chains. The vinyl silicone oil has a vinyl content of 0.1~0.8wt% and a viscosity of 300~1000 mPa·s at 25°C.

[0019] Preferably, the hydrogen-containing silicone oil is one or more of the following: terminal hydrogen-containing silicone oil, terminal methyl side hydrogen-containing silicone oil, and silicone oil containing hydrogen in both the terminal group and the side chain; the hydrogen content of the hydrogen-containing silicone oil is 0.1wt% to 1.5wt%, and the viscosity at 25°C is 20 to 800 mPa·s.

[0020] Preferably, the platinum catalyst is one or a combination of several of the following: an alcoholic solution of chloroplatinic acid, a platinum catalyst coordinated with tetrahydrofuran, and a platinum catalyst coordinated with divinyltetramethylsiloxane.

[0021] Preferably, the cerium-based heat resistant agent is one or more of cerium oxide nanoparticles, iron-cerium composite oxide, cerium-zirconium composite oxide, and cerium acetate.

[0022] Preferably, the polymerization inhibitor includes one or more of 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 2-methyl-3-butyn-2-ol, 3-phenyl-1-butynyl-3-ol, and 1,1,3,3-tetramethyl-1,3-divinylsiloxane.

[0023] Secondly, the present invention also provides a method for preparing the high-temperature resistant organosilicon gel, comprising the following steps: (S.1) Preparation of component A: Vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, cerium-based heat resistant agent and optional organosilicon compound containing dynamic reversible crosslinking groups are mixed evenly; (S.2) Preparation of component B: Vinyl silicone oil, platinum catalyst and optional organosilicon compound containing dynamic reversible crosslinking groups are mixed evenly; (S.3) The high-temperature resistant silicone gel is obtained by mixing and curing components A and B.

[0024] Thirdly, the present invention also provides the application of the high-temperature resistant silicone gel in power semiconductor packaging protection materials.

[0025] Therefore, this application has the following beneficial effects: (1) Breaking through the bottleneck of high temperature stability: Through the dynamic coordination cross-linking network (such as pyridine-zinc bond) to actively dissipate heat stress, combined with the main chain protection of cerium-based heat resistant agent, the gel can maintain excellent elasticity after long-term aging at 200℃, completely eliminating the problem of hardening and cracking, and breaking through the 150℃ service limit of traditional silicone gel. (2) Realize intelligent self-protection mechanism: the metal coordination bond can be reversibly broken and absorb energy under thermal stress. After the stress is eliminated, it can be quickly reorganized to repair micro-damage, forming a "molecular fuse" effect, which significantly improves the thermal shock resistance performance and is especially suitable for the thermal cycling conditions of power semiconductor packaging. (3) Balancing processability and reliability: The dynamic network remains inert during room temperature processing, maintaining a low viscosity of 300-800 mPa·s to ensure the applicability of precision potting; the intelligent activation protection function during high-temperature service does not require sacrificing processability or transparency, thus resolving the contradiction between heat resistance and workability. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0027] Example 1: Preparation of Component A: In a glove box filled with dry, high-purity nitrogen, the following raw materials were added to a 5 L planetary stirred tank: 80 parts vinyl polydimethylsiloxane (viscosity 300 mPa·s, vinyl content 0.15%), 10 parts side-chain vinyl polydimethylsiloxane (viscosity 600 mPa·s, vinyl content 0.7%), 6 parts methylhydrosilicone oil crosslinking agent (viscosity 45 mPa·s, hydrogen content 0.9%, active hydrogen content 0.12%), 9 parts vinyl-terminated amino silicone oil (viscosity 663 mPa·s, ammonia value 0.05 mmol / g), 0.08 parts composite inhibitor (composed of 0.04 parts ethynylcyclohexanol and 0.04 parts tetramethyltetravinylcyclotetrasiloxane), and 2.5 parts cerium oxide nanoparticles. The mixture was stirred at 40 rpm for 3 hours at room temperature to ensure thorough and uniform dispersion of all components. The mixture was then filtered through a 400-mesh filter to obtain a clear and transparent component A with a viscosity of 520 mPa·s (25°C). It was immediately sealed and packaged in a light-proof container.

[0028] Preparation of Component B: Under the same inert atmosphere and strictly light-protected conditions, the following raw materials were added to another stirred tank: 80 parts of the same vinyl polydimethylsiloxane as Component A, 1.6 parts of zinc acetylacetonate, 10 parts of the same side-chain vinyl polydimethylsiloxane, 1 part of a highly active platinum catalyst (platinum content 4000 ppm, solvent: vinyl silicone oil), and 1.2 parts of an adhesion promoter (composed of 0.6 parts of 3-glycidyl etheroxypropyltrimethoxysilane and 0.6 parts of 3-methacryloyloxypropyltrimethoxysilane). The mixture was stirred at room temperature in the dark for 2 hours, then filtered through a 400-mesh filter to obtain Component B, with a viscosity of 480 mPa·s (25°C). It was immediately sealed and packaged in a light-protected environment.

[0029] Curing and Testing: Components A and B were thoroughly mixed in a 1:1 weight ratio, degassed under vacuum (-0.098 MPa, 5 minutes), and then injected into a standard mold. After curing, a transparent, bubble-free, and smooth silicone gel was obtained. Its initial cone penetration was 52 (1 / 10 mm). After aging at 200℃ for 1000 hours, the cone penetration decreased to 49 (1 / 10 mm), with no cracking, stickiness, or powdering observed. The mixed viscosity was only 550 mPa·s, easily filling narrow gaps of 0.08 mm.

[0030] Example 2: Component A was prepared using 85 parts of lower viscosity terminal vinyl polydimethylsiloxane (viscosity 180 mPa·s, vinyl content 0.25%), 8 parts of side-chain vinyl polydimethylsiloxane (viscosity 400 mPa·s, vinyl content 0.85%), 4.6 parts of vinyl-terminated amino silicone oil (viscosity 680 mPa·s, ammonia value 0.1 mmol / g), and 5.5 parts of lower viscosity hydrogen-containing silicone oil crosslinking agent (viscosity 25 mPa·s, active hydrogen content 1.0%). The amount of composite inhibitor was reduced to 0.05 parts (ethynylcyclohexanol:tetramethyltetravinylcyclotetrasiloxane = 1:1.5) to shorten the inhibition time. 1.8 parts of iron-cerium composite oxide were also used. After stirring at 25°C for 2.5 hours, the mixture was filtered to obtain component A with a viscosity of only 350 mPa·s.

[0031] Component B was prepared as follows: 85 parts of vinyl-terminated polydimethylsiloxane (viscosity 180 mPa·s, vinyl content 0.25%), with the amount of highly active platinum catalyst increased to 2.0 parts (platinum content 4000 ppm) to accelerate curing. 0.8 parts of adhesion promoter (epoxy group: methacryloxy group = 1:1) and 4 parts of sodium iron ethylenediaminetetraacetate were added. After stirring in the dark for 2 hours, the mixture was filtered to obtain component B with a viscosity of approximately 320 mPa·s.

[0032] Curing and Testing: Components A and B are thoroughly mixed in a 1:1 weight ratio. After vacuum degassing (-0.098 MPa, 5 minutes), the mixture exhibits excellent flowability, capable of filling ultra-narrow gaps of 0.05 mm. The cured product is a transparent, bubble-free, and smooth silicone gel. The working time at 25°C is approximately 40 minutes. Complete curing at 70°C takes only 20 minutes. The initial cone penetration of the cured product is 56 (0.1 mm). The cone penetration at 200°C / 1000 h is 52 (0.1 mm), demonstrating stable performance.

[0033] Example 3: Component A was prepared using 75 parts of terminal vinyl silicone oil (viscosity 300 mPa·s, vinyl content 0.1%), 12 parts of side-chain vinyl silicone oil (viscosity 750 mPa·s, vinyl content 0.55%), 7 parts of hydrogen-containing silicone oil crosslinking agent (viscosity 70 mPa·s, hydrogen content 0.75%), 0.43 parts of carboxyl silicone oil (viscosity 150 mPa·s, hydrogen content 0.15%, carboxyl value 0.15 mmol / g), and 0.12 parts of a composite inhibitor (ethynylcyclohexanol:vinylsiloxane = 1:2). The amount of cerium oxide nanoparticles was significantly increased to 3.0 parts. The viscosity of the prepared component A was approximately 600 mPa·s.

[0034] Component B was prepared by adding 75 parts of the same vinyl-terminated silicone oil as component A, 2.8 parts of a platinum catalyst (platinum content 3500 ppm), 0.0075 parts of ferric stearate, and increasing the amount of adhesion promoter to 1.8 parts (1:1 mixture) to enhance adhesion to the substrate and resist thermal stress. The viscosity of component B was approximately 550 mPa·s.

[0035] Curing and Testing: Components A and B are thoroughly mixed in a 1:1 weight ratio. After vacuum degassing (-0.098 MPa, 5 minutes), the mixture exhibits excellent flowability, capable of filling ultra-narrow gaps of 0.05 mm. After curing, a transparent, bubble-free, and smooth silicone gel is obtained. After undergoing 1000 cycles of thermal shock testing within a temperature range of -55℃ to 200℃, the cured gel showed no signs of detachment from the substrate (e.g., PCB, ceramic), cracking, or significant performance degradation. Its high-temperature aging resistance is also excellent, with a cone penetration change rate of <10% after 200℃ / 1000h.

[0036] Example 4: Preparation of Component A: Optimized based on Example 1. 78 parts of terminal vinyl silicone oil (viscosity 480 mPa·s), 12 parts of side-chain vinyl silicone oil (viscosity 650 mPa·s). 5.5 parts of a branched hydrogen-containing silicone oil with appropriate hydrogen content (viscosity 60 mPa·s, hydrogen content 0.8%) were used to form a more robust network structure. 5.4 parts of vinyl-terminated amino silicone oil (viscosity 680 mPa·s, ammonia value 0.1 mmol / g). 0.09 parts of a complex inhibitor (1:1). 2.2 parts of cerium acetate. The viscosity of Component A is approximately 500 mPa·s.

[0037] Component B was prepared as follows: 78 parts of vinyl-terminated silicone oil (viscosity 480 mPa·s), 3.0 parts of platinum catalyst (platinum content 4000 ppm), 1.6 parts of zinc acetylacetonate, and 1.5 parts of adhesion promoter (3-glycidyl etheroxypropyltrimethoxysilane:3-methacryloyloxypropyltrimethoxysilane = 1:0.8), with optimized adhesion to plastics (such as PPS, PBT) and metal frames. The viscosity of component B is approximately 460 mPa·s.

[0038] Curing and Testing: Components A and B are thoroughly mixed in a 1:1 weight ratio. After vacuum degassing (-0.098 MPa, 5 minutes), the mixture exhibits excellent flowability, capable of filling ultra-narrow gaps of 0.05 mm. After curing, a transparent, bubble-free, and smooth silicone gel is obtained. In addition to excellent heat resistance (electrical strength retention >90% after aging at 200℃ / 1000h) and low volatile content (0.81%), the cured product maintains a volume resistivity of 1.0 × 10⁻⁶. 15 With a dielectric constant above Ω·cm, it is stable and very suitable for high-voltage, high-reliability power semiconductor packaging protection.

[0039] Example 5: Preparation of Component A: In a glove box filled with dry, high-purity nitrogen, the following raw materials were added to a 5 L planetary stirred tank: 80 parts vinyl polydimethylsiloxane (viscosity 300 mPa·s, vinyl content 0.15%), 6 parts side-chain vinyl polydimethylsiloxane (viscosity 100 mPa·s, vinyl content 0.6%), 4 parts methylhydrosilicone oil crosslinking agent (viscosity 45 mPa·s, active hydrogen content 1.5%), 2.2 parts vinyl-terminated amino silicone oil (viscosity 500 mPa·s, ammonia value 0.12 mmol / g), 0.06 parts composite inhibitor (composed of 0.04 parts ethynylcyclohexanol and 0.02 parts tetramethyltetravinylcyclotetrasiloxane), and 2.5 parts cerium-zirconium composite oxide. The mixture was stirred at 40 rpm for 3 hours at room temperature to ensure thorough and uniform dispersion of all components. The mixture was then filtered through a 400-mesh filter to obtain a clear and transparent Component A with a viscosity of 550 mPa·s (25℃). Immediately seal and protect from light.

[0040] Preparation of Component B: Under the same inert atmosphere and strictly light-protected conditions, the following raw materials were added to another stirred tank: 80 parts of vinyl polydimethylsiloxane (identical to Component A), 10 parts of side-chain vinyl polydimethylsiloxane, 1 part of highly active platinum catalyst (platinum content 4000 ppm, solvent: vinyl silicone oil), 1.35 parts of zinc acetylacetonate, and 1.2 parts of adhesion promoter (composed of 0.6 parts of 3-glycidyl etheroxypropyltrimethoxysilane and 0.6 parts of 3-methacryloyloxypropyltrimethoxysilane). The mixture was stirred at room temperature in the dark for 2 hours, then filtered through a 400-mesh filter to obtain Component B, with a viscosity of 480 mPa·s (25°C). It was immediately sealed and packaged in a light-protected environment.

[0041] Curing and Testing: Components A and B were thoroughly mixed in a 1:1 weight ratio, vacuum degassed (-0.098 MPa, 5 minutes), and then injected into a standard mold. After curing, a transparent, bubble-free, and smooth silicone gel was obtained. In addition to excellent heat resistance (electrical strength retention >90% after aging at 200℃ / 1000h) and low volatile content (0.81%), the cured product consistently maintained a volume resistivity of 1.0 × 10⁻⁶. 15 With a dielectric constant above Ω·cm, it is stable and very suitable for high-voltage, high-reliability power semiconductor packaging protection.

[0042] Comparative Example 1: Preparation of Component A: 95 parts of ordinary vinyl-terminated silicone oil (viscosity 500 mPa·s, vinyl content 0.1%), without side-chain vinyl silicone oil. 5 parts of ordinary hydrogen-containing silicone oil crosslinking agent (viscosity 100 mPa·s, hydrogen content 0.5%). 0.1 parts of a single ethynylcyclohexanol was added as an inhibitor. No heat stabilizers were added. The mixture was stirred and mixed according to conventional methods to obtain Component A.

[0043] Preparation of Component B: 95 parts of the same ordinary vinyl-terminated silicone oil as Component A were used. 1.0 part of ordinary platinum catalyst (platinum content 3000 ppm) was added. No adhesion promoter was added. Component B was obtained by mixing in the dark using conventional methods.

[0044] Curing and Testing: Components A and B were mixed in a 1:1 ratio, resulting in a mixed viscosity of approximately 650 mPa·s. The flowability was acceptable. After curing at 100°C for 30 minutes, the initial properties were similar to those of Example 1 (initial cone penetration of 52 (1 / 10 mm)). However, after aging at 200°C for 500 hours, the material surface had significantly hardened, the cone penetration decreased to 25 (1 / 10 mm), and elasticity was lost. Further aging to 1000 hours resulted in severe degradation, brittleness, and cracking of the material, rendering it ineffective for protection. This comparative example clearly demonstrates that without the specific component design and synergistic action of this invention, it is impossible to achieve the combined properties of low viscosity, excellent high-temperature resistance, and low volatility.

[0045] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that no vinyl-terminated amino silicone oil was added to component A and no zinc acetylacetone was added to component B, while the other conditions were the same as in Example 1.

[0046] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that zinc acetylacetone was not added to component B, while the other conditions were the same as in Example 1.

[0047] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that sodium acetylacetonate was added to component B to replace zinc acetylacetonate, while the other conditions were the same as in Example 1.

[0048] The test results of the silica gels prepared in Examples 1-5 and Comparative Examples 1-4 are summarized in Table 1 below: Table 1 Performance indicators Mixed viscosity (mPa·s) Operation time (min) Initial cone penetration (1 / 4 cone) 200℃ / 1000h (1 / 10mm) Volume resistivity (Ω·cm) Test methods / conditions GB / T2794-2013 Viscosity doubling time at 25℃ GB / T269-1991 - GB / T1410-2006 Example 1 550 >60 52 49 <![CDATA[1.8×10 15 ]]> Example 2 380 ~40 56 52 <![CDATA[1.9×10 15 ]]> Example 3 610 >70 49 45 <![CDATA[1.6×10 15 ]]> Example 4 530 >60 56 51 <![CDATA[2.2×10 15 ]]> Example 5 460 >60 53 47 <![CDATA[1.8×10 15 ]]> Comparative Example 1 650 >60 52 25 <![CDATA[1.2×10 15 ]]> Comparative Example 2 560 >60 48 23 <![CDATA[2.2×10 15 ]]> Comparative Example 3 550 >60 49 27 <![CDATA[2.1×10 15 ]]> Comparative Example 4 550 >60 49 29 <![CDATA[1.4×10 15 ]]> As shown in Table 1 above, the dynamic coordination crosslinking network of the silicone gel in this application actively dissipates heat stress. Combined with the main chain protection of the cerium-based heat-resistant agent, the gel maintains excellent elasticity even after long-term aging at 200℃, completely eliminating the problem of hardening cracking and breaking through the traditional silicone gel's 150℃ service limit. Furthermore, the dynamic network in the silicone gel remains inert during room temperature processing, thus maintaining a low viscosity of 300-800 mPa·s, ensuring suitability for precision potting. During high-temperature service, it intelligently activates its protective function without sacrificing processability or transparency, resolving the contradiction between heat resistance and workability.

[0049] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A high-temperature resistant silicone gel, formed by mixing and curing component A and component B, wherein component A comprises vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, and cerium-based heat resistant agent, and component B comprises vinyl silicone oil and platinum catalyst, characterized in that: The components A and / or B further contain organosilicon compounds with dynamically reversible crosslinking groups, thereby enabling the formation of a dynamic crosslinking network with energy dissipation capabilities at high temperatures on the basis of the crosslinking network formed by the addition of vinyl silicone oil and hydrogen-containing silicone oil under the catalysis of a platinum catalyst.

2. The high-temperature resistant organosilicon gel according to claim 1, characterized in that: The dynamic reversible crosslinking group is a coordination crosslinking group, which is composed of an electron-donating group and a metal ion; The electron-donating group is selected from pyridyl, carboxyl, or amino groups; The metal ions are selected from zinc ions, iron ions, or copper ions.

3. The high-temperature resistant organosilicon gel according to claim 2, characterized in that: The electron-donating group is derived from vinyl silicone oil or hydrogen-containing silicone oil whose side chain or end group contains the electron-donating group. The metal ions are derived from metal carboxylates or metal chelates added to component A or component B.

4. The high-temperature resistant organosilicon gel according to claim 3, characterized in that: The metal carboxylate or metal chelate is selected from zinc acetylacetonate, iron stearate, copper naphthenate, or sodium iron ethylenediaminetetraacetate.

5. A high-temperature resistant organosilicon gel according to any one of claims 1-4, characterized in that: The vinyl silicone oil includes one or more of the following: terminal vinyl silicone oil, vinyl-terminated diphenyl-dimethyl copolymer silicone oil, side vinyl silicone oil, and silicone oil containing vinyl groups and side chains. The vinyl silicone oil has a vinyl content of 0.1~0.85wt% and a viscosity of 300~1000 mPa·s at 25°C.

6. A high-temperature resistant organosilicon gel according to any one of claims 1-4, characterized in that: The hydrogen-containing silicone oil is one or more of the following: terminal hydrogen-containing silicone oil, terminal methyl side hydrogen-containing silicone oil, and silicone oil containing hydrogen in both the terminal group and the side chain; the active hydrogen content of the hydrogen-containing silicone oil is 0.1wt% to 1.5wt%, and the viscosity at 25°C is 20 to 800 mPa·s.

7. A high-temperature resistant organosilicon gel according to any one of claims 1-4, characterized in that: The platinum catalyst is one or a combination of several of the following: an alcoholic solution of chloroplatinic acid, a platinum catalyst coordinated with tetrahydrofuran, and a platinum catalyst coordinated with divinyltetramethylsiloxane.

8. A high-temperature resistant organosilicon gel according to any one of claims 1-4, characterized in that: The cerium-based heat resistant agent is one or more of cerium oxide nanoparticles, iron-cerium composite oxide, cerium-zirconium composite oxide, and cerium acetate. The polymerization inhibitor includes one or more of 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 2-methyl-3-butyn-2-ol, 3-phenyl-1-butynyl-3-ol, and 1,1,3,3-tetramethyl-1,3-divinylsiloxane.

9. The method for preparing the high-temperature resistant organosilicon gel according to any one of claims 1-8, characterized in that, Includes the following steps: (S.1) Preparation of component A: Vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, cerium-based heat resistant agent and optional organosilicon compound containing dynamic reversible crosslinking groups are mixed evenly; (S.2) Preparation of component B: Vinyl silicone oil, platinum catalyst and optional organosilicon compound containing dynamic reversible crosslinking groups are mixed evenly; (S.3) The high-temperature resistant silicone gel is obtained by mixing and curing components A and B.

10. The application of the high-temperature resistant silicone gel as described in any one of claims 1-8 in power semiconductor packaging protection materials.