A method for preparing a high-cyclic-load-resistant silicone sealant

Abstract

This invention relates to the field of silicone sealing materials technology, and discloses a high-cyclic-load-resistant silicone adhesive and its preparation method. The silicone adhesive uses α,ω-dihydroxypolydimethylsiloxane as a matrix, incorporates methyl / phenyl-containing organosilicon resin and nano-activated calcium carbonate, and is combined with an alkoxysilane crosslinking agent, a titanate catalyst, and an aluminate coupling agent or a long-chain alkylsilane interface agent. Through vacuum kneading and planetary stirring curing, a flexible silicone rubber network and a rigid silicone resin network interpenetrate structure are formed. This silicone adhesive significantly improves tear strength and mechanical fatigue life under large displacement tensile-compression cyclic loading while maintaining conventional mechanical and adhesive properties.

Description

Technical Field

[0001] This invention relates to the field of silicone sealing materials technology, and in particular to a method for preparing a high-cyclic-load-resistant silicone sealant. Background Technology

[0002] De-alcoholized, one-component condensation-type room temperature vulcanizing (RTV-1) silicone sealant is typically based on α,ω-dihydroxy polydimethylsiloxane as a base polymer, combined with alkoxysilane crosslinking agents, fillers, plasticizers, coupling agents, and catalysts. It is stored in moisture-proof packaging and cures into an elastomer after application by relying on moisture in the air. It features excellent weather resistance, a wide temperature range, and good adhesion, and is widely used in areas such as sealing joints in building curtain walls.

[0003] In glass curtain walls, metal curtain walls, and stone curtain walls, joints are subjected to repeated tension and compression caused by temperature changes, wind loads, and deformation of the main structure. The sealant is under constant high-displacement cyclic loading. If the material's tear resistance and mechanical fatigue resistance are insufficient, cracks can easily initiate at the gaps and gradually propagate, ultimately leading to sealant failure. Therefore, significantly improving tear strength and cyclic fatigue life while ensuring conventional mechanical and adhesive properties is a crucial technical requirement for silicone sealants used in construction.

[0004] CN119842362A discloses a high tear strength and fatigue resistance dealcoholized silicone sealant and its preparation method. The sealant is composed of α,ω-dihydroxy polysiloxane, polyborosiloxane, dimethyl silicone oil, nano-activated calcium carbonate, alkoxysilane crosslinking agent, complex crosslinking agent, and two titanate curing agents. This method improves the energy dissipation capacity of the material under cyclic loading by forming a BO dynamic bond-based network through polyborosiloxane. Long-chain fatty acid modification of nano-calcium carbonate using isopropyl tripearate titanate enhances the interaction between the polymer and inorganic filler, thereby improving the tear strength and mechanical fatigue resistance of the silicone sealant to some extent. However, it relies on a large proportion of polyborosiloxane and isopropyl tripearate titanate, resulting in a complex system structure, and the long-term stability and interface reinforcement effect of the dynamic BO network remain limited. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to construct an interpenetrating double network of α,ω-dihydroxyPDMS-organosilicon resin and optimize the polymer-nano-calcium carbonate interface structure, so as to significantly improve the tear strength and mechanical fatigue life under high displacement and high cycle tensile-compression cyclic loading of the de-alcoholized silicone sealant while keeping the conventional mechanical and adhesive properties of the sealant basically unchanged.

[0006] To achieve the above objectives, the present invention provides a high cyclic loading resistant silicone sealant, comprising, by weight, 100 parts of α,ω-dihydroxypolydimethylsiloxane, 5-40 parts of organosilicon resin, 5-20 parts of dimethyl silicone oil, 70-140 parts of nano-activated calcium carbonate, 3-10 parts of alkoxysilane crosslinking agent, 1-5 parts of silane coupling agent, 1-5 parts of titanate catalyst, and 0.5-5 parts of interface agent.

[0007] Preferably, the silicone resin is a methyl / phenyl MQ type silicone resin with silanol groups at the ends or on the side groups, and the silanol content is 3-10 wt%. More preferably, the amount of the silicone resin used is 10-30 parts.

[0008] Preferably, the alkoxysilane crosslinking agent includes one or more of methyltrimethoxysilane, n-octyltrimethoxysilane, and phenyltriethoxysilane.

[0009] Preferably, the silane coupling agent comprises at least one of γ-aminopropyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane.

[0010] Preferably, the titanate catalyst is diisopropyl bis(ethyl acetoacetate) titanate.

[0011] Preferably, the interface agent is selected from one or more of aluminate coupling agents, triethoxyoctadecylsilane, and isopropyl titanate tristearate. More preferably, the interface agent is aluminate coupling agent DL-411A.

[0012] Preferably, the average particle size of the nano-active calcium carbonate is 100-150 nm.

[0013] This invention also discloses a method for preparing the above-mentioned high cyclic loading resistant silicone sealant, comprising the following steps: (1) Based on 100 parts by weight of α,ω-dihydroxy polydimethylsiloxane, 100 parts of α,ω-dihydroxy polydimethylsiloxane, 5-40 parts of organosilicon resin, 5-20 parts of dimethyl silicone oil and 70-140 parts of nano-active calcium carbonate are added to a kneader and dehydrated and mixed for 30-300 minutes at 80-150℃ and absolute pressure of 0.001-0.05MPa to obtain a uniform base material I; (2) At room temperature, transfer base material I to a planetary mixer or a high-speed dispersing mixer, add 3-10 parts of alkoxysilane crosslinking agent, and stir for 5-30 minutes under an absolute pressure of 0.005-0.08 MPa and a rotation speed of 10-800 rpm to obtain base material II; (3) Add 1-5 parts of silane coupling agent, 1-5 parts of titanate catalyst and 0.5-5 parts of interface agent to base material II at room temperature, stir and react for 30-120 minutes under absolute pressure of 0.001-0.05MPa and rotation speed of 50-500rpm, and degas to obtain high cyclic load resistant silicone sealant.

[0014] The beneficial effects of this invention are: This invention introduces methyl / phenyl-containing organosilicon resin into a traditional dealcoholized α,ω-dihydroxy PDMS matrix. Through alkoxysilane crosslinking and titanate catalysis, a dual-network structure is constructed in which a flexible silicone rubber network and a rigid silicone resin network interpenetrate. This enables the material to have better stress dispersion and energy dissipation capabilities when subjected to large displacement tensile-compression cyclic loads, and significantly improves tear strength and mechanical fatigue life.

[0015] This invention uses aluminate coupling agent DL-411A and / or triethoxyoctadecylsilane to modify the interface of nano-active calcium carbonate, so that a stable chemical or coordination bond is formed between the filler surface and the PDMS-organosilicon resin dual network, and long-chain organic groups are introduced to form a flexible hydrophobic shell, thereby further enhancing the interfacial bonding strength of polymer-inorganic filler, optimizing the crack propagation path, and making the tear strength and fatigue life significantly better than the formulation modified only with tristearate titanate isopropyl ester.

[0016] Under the synergistic effect of the above-mentioned dual-network structure and interface regulation, the tensile bond strength at 23°C and the elongation at maximum tension of Examples 1-5 of the present invention are similar to those of the comparative examples, and can meet the basic requirements of de-alcoholized silicone sealant for building applications. This shows that while significantly improving tear and fatigue resistance, the present invention does not have a significant negative impact on conventional mechanical and adhesive properties, and has both mechanical reliability and engineering applicability. Detailed Implementation

[0017] The parameters and sources of some raw materials in the examples are as follows: α,ω-dihydroxypolydimethylsiloxane with a viscosity of 50000 mPa·s.

[0018] Organosilicon resin: Model RSN-0217, silanol content 6wt%, brand: Dow Corning.

[0019] Dimethyl silicone oil with a viscosity of 500 mPa·s.

[0020] Nano-activated calcium carbonate with an average particle size of 120 nm.

[0021] Diisopropyl bis(ethyl acetoacetate) titanate: CAS No. 27858-32-8.

[0022] Isopropyl tristearate titanate: CAS No. 61417-49-0.

[0023] The aluminate coupling agent DL-411A is sourced from Nanjing Pinning Coupling Agent Co., Ltd. Example

[0024] A method for preparing a high-cyclic-load-resistant silicone sealant includes the following steps: (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane, 20 parts of organosilicon resin, 10 parts of dimethyl silicone oil and 110 parts of nano-activated calcium carbonate were added to a kneader and dehydrated and mixed for 180 min at 120℃ and 0.01 MPa absolute pressure to obtain uniform base material I, which was cooled to room temperature for later use. In this step, organosilicon resin and α,ω-dihydroxy polydimethylsiloxane partially condensed under high temperature and a small amount of Si-OH / Si-OR to form a rigid Si-O-Si network prototype mainly composed of silicone resin, which was uniformly dispersed in the flexible PDMS phase to provide a prestructure for subsequent construction of interpenetrating network. (2) Transfer the base material I obtained in step (1) to a planetary mixer, add 3.5 parts of methyltrimethoxysilane, 1.5 parts of n-octyltrimethoxysilane and 1.5 parts of phenyltriethoxysilane in sequence at room temperature, and stir for 15 min under an absolute pressure of 0.06 MPa and a rotation speed of 150 rpm to obtain base material II; in this step, the low molecular weight alkoxysilane and the terminal hydroxyl group of α,ω-dihydroxyPDMS undergo pre-condensation to form the precursor structure of the flexible silicone rubber permanent network; (3) At room temperature, base material II is kept in the planetary mixer, and 1.5 parts of γ-aminopropyltrimethoxysilane, 0.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts of diisopropyl bis(ethyl acetoacetate) titanate and 2.5 parts of tristearate titanate are added in sequence. The mixture is stirred and reacted for 40 minutes under an absolute pressure of 0.01 MPa and a rotation speed of 300 rpm to obtain a uniformly defoamed paste, namely a high cyclic load-resistant silicone sealant. It is then sealed in a dry and sealed packaging container for later use.

[0025] Among them, diisopropyl bis(ethyl acetoacetate) titanate promotes the condensation crosslinking of α,ω-dihydroxyPDMS and alkoxysilane to construct a flexible silicone rubber permanent network; isopropyl tristearate titanate coats the surface of nano-active calcium carbonate with long-chain fatty acids and combines with siloxane segments, so that the rigid organosilicon resin network and the flexible silicone rubber network form a tight coupling at the filler interface, thereby obtaining an interpenetrating double network structure with the silicone rubber network as the continuous phase and the organosilicon resin network as the rigid phase, which is beneficial for dispersing stress and inhibiting crack propagation under high-cycle tensile-compression cyclic loading. Example

[0026] A method for preparing a high-cyclic-load-resistant silicone sealant includes the following steps: (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane, 10 parts of organosilicon resin, 10 parts of dimethyl silicone oil and 110 parts of nano-active calcium carbonate were added to a kneader, dehydrated and mixed for 180 min at 120℃ and 0.01MPa absolute pressure to obtain uniform base material I, which was then cooled to room temperature for later use. (2) Transfer the base material I obtained in step (1) to a planetary mixer, add 3.8 parts of methyltrimethoxysilane, 1.5 parts of n-octyltrimethoxysilane and 1.2 parts of phenyltriethoxysilane in sequence at room temperature, and stir for 15 minutes under an absolute pressure of 0.06 MPa and a rotation speed of 150 rpm to obtain base material II; (3) At room temperature, base material II is kept in the planetary mixer, and 1.5 parts of γ-aminopropyltrimethoxysilane, 0.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts of diisopropyl bis(ethyl acetoacetate) titanate and 2.5 parts of tristearate titanate are added in sequence. The mixture is stirred and reacted for 40 minutes under an absolute pressure of 0.01 MPa and a rotation speed of 300 rpm to obtain a uniformly defoamed paste, namely a high cyclic load-resistant silicone sealant. It is then sealed in a dry and sealed packaging container for later use.

[0027] Compared to Example 1, the amount of silicone resin used is lower, only 10 parts, and the content of rigid network is less. Although the expected tear strength and fatigue resistance are better than the single-network formulation without silicone resin, they are lower than those of Examples 1 and 3. Example

[0028] A method for preparing a high-cyclic-load-resistant silicone sealant includes the following steps: (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane, 30 parts of organosilicon resin, 10 parts of dimethyl silicone oil and 110 parts of nano-active calcium carbonate were added to a kneader, dehydrated and mixed for 180 min at 120℃ and 0.01 MPa absolute pressure to obtain uniform base material I, which was then cooled to room temperature for later use. (2) Transfer the base material I obtained in step (1) to a planetary mixer, add 3.2 parts of methyltrimethoxysilane, 1.5 parts of n-octyltrimethoxysilane and 1.8 parts of phenyltriethoxysilane in sequence at room temperature, and stir for 15 minutes under an absolute pressure of 0.06 MPa and a rotation speed of 150 rpm to obtain base material II; (3) At room temperature, base material II is kept in the planetary mixer, and 1.5 parts of γ-aminopropyltrimethoxysilane, 0.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts of diisopropyl bis(ethyl acetoacetate) titanate and 2.5 parts of tristearate titanate are added in sequence. The mixture is stirred and reacted for 40 minutes under an absolute pressure of 0.01 MPa and a rotation speed of 300 rpm to obtain a uniformly defoamed paste, namely a high cyclic load-resistant silicone sealant. It is then sealed in a dry and sealed packaging container for later use.

[0029] Compared with Example 1, the amount of silicone resin was increased to 30 parts, the proportion of rigid silicone resin network was further increased, the shear hardening and energy dissipation capacity were enhanced, and the expected tear strength and fatigue life were slightly higher than those of Example 1.

[0030] Comparative Example 1 A method for preparing silicone sealant includes the following steps: (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane, 10 parts of dimethyl silicone oil and 110 parts of nano-active calcium carbonate were added to a kneader, dehydrated and mixed for 180 min at 120℃ and 0.01 MPa absolute pressure to obtain uniform base material A, which was then cooled to room temperature for later use. (2) Transfer base material A to a planetary mixer, add 5.5 parts of methyltrimethoxysilane, 1.5 parts of γ-aminopropyltrimethoxysilane and 0.5 parts of γ-glycidoxypropyltrimethoxysilane in sequence at room temperature, and stir for 15 min under an absolute pressure of 0.06 MPa and a rotation speed of 150 rpm to obtain base material B; (3) Add 4 parts of diisopropyl bis(ethyl acetoacetate) titanate to base material B at room temperature, and stir for 40 min under absolute pressure of 0.01 MPa and rotation speed of 300 rpm to obtain a uniformly degassed silicone sealant, which is then placed in a dry and sealed packaging container for later use.

[0031] This comparative example did not include silicone resin or isopropyl tristearate titanate. It only formed a single silicone rubber network by crosslinking α,ω-dihydroxyPDMS with small molecule alkoxysilane. Under high-cycle loading, the internal stress was mainly concentrated in this single network, which easily led to crack initiation and rapid propagation, resulting in poor fatigue resistance.

[0032] Comparative Example 2 A method for preparing a high-cyclic-load-resistant silicone sealant includes the following steps: (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane, 20 parts of organosilicon resin, 10 parts of dimethyl silicone oil and 110 parts of nano-active calcium carbonate were added to a kneader, dehydrated and mixed for 180 min at 120℃ and 0.01 MPa absolute pressure to obtain uniform base material I, which was then cooled to room temperature for later use. (2) Transfer the base material I obtained in step (1) to a planetary mixer, add 3.5 parts of methyltrimethoxysilane, 1.5 parts of n-octyltrimethoxysilane and 1.5 parts of phenyltriethoxysilane in sequence at room temperature, and stir for 15 minutes under an absolute pressure of 0.06 MPa and a rotation speed of 150 rpm to obtain base material II; (3) At room temperature, base material II is kept in the planetary mixer, and 1.5 parts of γ-aminopropyltrimethoxysilane, 0.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane and 3 parts of diisopropyl bis(ethyl acetoacetate) titanate are added in sequence. The mixture is stirred for 40 minutes under an absolute pressure of 0.01 MPa and a rotation speed of 300 rpm to obtain a uniform defoamed paste, namely a high cyclic load resistant silicone sealant. It is then sealed in a dry and sealed packaging container for later use. Example

[0033] A method for preparing a high-cyclic-load-resistant silicone sealant includes the following steps: (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane, 30 parts of organosilicon resin, 10 parts of dimethyl silicone oil and 110 parts of nano-active calcium carbonate were added to a kneader, dehydrated and mixed for 180 min at 120℃ and 0.01 MPa absolute pressure to obtain uniform base material I, which was then cooled to room temperature for later use. (2) Transfer the base material I obtained in step (1) to a planetary mixer, add 3.2 parts of methyltrimethoxysilane, 1.5 parts of n-octyltrimethoxysilane and 1.8 parts of phenyltriethoxysilane in sequence at room temperature, and stir for 15 minutes under an absolute pressure of 0.06 MPa and a rotation speed of 150 rpm to obtain base material II; (3) At room temperature, base material II is kept in the planetary mixer, and 1.5 parts of γ-aminopropyltrimethoxysilane, 0.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts of diisopropyl bis(ethyl acetoacetate) titanate and 2.5 parts of aluminate coupling agent DL-411A are added in sequence. The mixture is stirred and reacted for 40 minutes under an absolute pressure of 0.01 MPa and a rotation speed of 300 rpm to obtain a uniform defoamed paste, namely a high cyclic load silicone sealant. It is then sealed in a dry and sealed packaging container for later use. Example

[0034] A method for preparing a high-cyclic-load-resistant silicone sealant includes the following steps: (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane, 30 parts of organosilicon resin, 10 parts of dimethyl silicone oil and 110 parts of nano-active calcium carbonate were added to a kneader, dehydrated and mixed for 180 min at 120℃ and 0.01 MPa absolute pressure to obtain uniform base material I, which was then cooled to room temperature for later use. (2) Transfer the base material I obtained in step (1) to a planetary mixer, add 3.2 parts of methyltrimethoxysilane, 1.5 parts of n-octyltrimethoxysilane and 1.8 parts of phenyltriethoxysilane in sequence at room temperature, and stir for 15 minutes under an absolute pressure of 0.06 MPa and a rotation speed of 150 rpm to obtain base material II; (3) At room temperature, base material II is kept in the planetary mixer, and 1.5 parts of γ-aminopropyltrimethoxysilane, 0.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts of diisopropyl bis(ethyl acetoacetate) titanate and 2.5 parts of triethoxyoctadecylsilane are added in sequence. The mixture is stirred and reacted for 40 minutes under an absolute pressure of 0.01 MPa and a rotation speed of 300 rpm to obtain a uniformly defoamed paste, namely a high cyclic load-resistant silicone sealant. It is then sealed in a dry and sealed packaging container for later use.

[0035] Test Example 1 Tensile bond strength and elongation at maximum tension: Specimens were prepared according to GB / T 13477.8-2017 Test methods for building sealing materials - Part 8: Determination of tensile adhesion, and tested after curing at 23±2℃ and 50±10% relative humidity for 28 days.

[0036] Tear strength: The tear strength shall be determined according to Method B (right-angled specimen) in GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)". The specimen shall be cut into a right-angled tear specimen with a pre-made tear and the tear strength shall be determined at 23°C and a specified tensile speed.

[0037] Mechanical fatigue resistance: 1) Specimen preparation: Dumbbell-shaped bonding specimens were prepared in accordance with GB / T 13477.8-2017. The substrate was glass or aluminum alloy, and the bonding dimensions and substrate treatment methods were performed in accordance with the standard. 2) Curing conditions: The specimens were cured at 23±2℃ and 50±10% relative humidity for 28 days; 3) Loop loading condition: The displacement control mode was used, and the test was conducted on an electronic tensile fatigue testing machine. Based on the initial seam width, apply a cyclic tensile-compression deformation of ±35%; The cyclic waveform is a sine wave; The cycle time is 300 seconds per cycle; 4) Failure determination: Referring to the determination principle of bond failure in GB / T 13477.10-2017, when the specimen shows a through crack or the length of the bond interface failure exceeds 2 mm, it is determined to be a failure. (5) Results: Record the number of cycles when the specimen fails. There should be no less than 3 specimens in each group. Take the average value as the mechanical fatigue life.

[0038] Table 1. Test results of mechanical properties and resistance to mechanical fatigue

[0039] As shown in Table 1, Examples 1-5 and Comparative Example 1 showed little difference in tensile bond strength and elongation at maximum tension at 23°C. The tensile bond strength was between 0.78 and 0.81 MPa, and the elongation at maximum tension was between 245 and 260%. This indicates that introducing silicone resin and different interface agents into the silicone system and constructing an interpenetrating double network did not significantly sacrifice the conventional mechanical and adhesive properties of the sealant.

[0040] Compared to Comparative Example 1, which contains neither silicone resin nor interface agent, the tear strength in Examples 1-3 increased from 5.8 N·mm when the amount of silicone resin was increased from 0 to 10, 20, and 30 parts, respectively. -1 Increased to 7.2, 8.0, and 9.4 N·mm -1 The number of mechanical fatigue cycles increased from 170 to 410, 600, and 640, respectively. In Comparative Example 2, with only 20 parts of silicone resin added, the tear strength and fatigue life were also significantly better than in Comparative Example 1. It is evident that introducing an appropriate amount of silicone resin into the α,ω-dihydroxy PDMS network to form a rigid silicone resin network is key to improving tear strength and cyclic fatigue life. Furthermore, under the conditions given in this invention, a silicone resin dosage of 20-30 parts yields superior overall performance.

[0041] With the same amount of silicone resin, Example 3 used isopropyl tristearate titanate, Example 4 used aluminate coupling agent DL-411A, and Example 5 used triethoxyoctadecylsilane. Compared to the other two, Example 4 exhibited the highest tear strength and resistance to mechanical fatigue cycles, both at 9.8 N·mm. -1 And 700 times, which is better than the 9.4 N·mm of Example 3. -1 And 640 times, which is also higher than the 9.6 N·mm in Example 5. -1 The results of 660 cycles indicate that the synergistic effect between the aluminate coupling agent DL-411A and the PDMS-silicone resin interpenetrating dual network is most significant. Example 5 also shows a certain improvement over Example 3, indicating that long-chain alkylsilanes, by forming a covalently anchored, flexible alkyl shell on the filler surface, are also beneficial for improving interfacial bonding strength and fatigue crack resistance.

[0042] In summary, by constructing a rigid network with organosilicon resin and using the preferred aluminate coupling agent DL-411A or long-chain alkylsilane as an interface agent, the silicone adhesive of the present invention exhibits significantly better tear strength and mechanical fatigue life than single-network formulations and formulations containing only organosilicon resin without an interface agent, while maintaining conventional mechanical and adhesive properties.

[0043] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A high-cyclic-load-resistance silicone sealant, characterized in that: By weight, it includes 100 parts of α,ω-dihydroxypolydimethylsiloxane, 5-40 parts of organosilicon resin, 5-20 parts of dimethyl silicone oil, 70-140 parts of nano-activated calcium carbonate, 3-10 parts of alkoxysilane crosslinking agent, 1-5 parts of silane coupling agent, 1-5 parts of titanate catalyst, and 0.5-5 parts of interface agent.

2. The high cyclic loading resistant silicone sealant as described in claim 1, characterized in that: The organosilicon resin is a methyl / phenyl MQ type silicone resin with silanol groups at the ends or on the side groups, and its silanol content is 3-10 wt%.

3. The high cyclic loading resistant silicone sealant as described in claim 1, characterized in that: The alkoxysilane crosslinking agent includes one or more of methyltrimethoxysilane, n-octyltrimethoxysilane, and phenyltriethoxysilane.

4. The high cyclic loading resistant silicone sealant as described in claim 1, characterized in that: The silane coupling agent includes at least one of γ-aminopropyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane.

5. The high cyclic loading resistant silicone sealant as described in claim 1, characterized in that: The titanate catalyst is diisopropyl bis(ethyl acetoacetate) titanate.

6. The high cyclic loading resistant silicone sealant as described in claim 1, characterized in that: The interface agent is selected from one or more of the following: aluminate coupling agent DL-411A, triethoxyoctadecylsilane, and isopropyl tristearate titanate.

7. The high cyclic loading resistant silicone sealant as described in claim 6, characterized in that: The interface agent is an aluminate coupling agent DL-411A.

8. The high cyclic loading resistant silicone sealant as described in claim 1, characterized in that: The average particle size of the nano-active calcium carbonate is 100-150 nm.

9. A method for preparing a high-cyclic-load-resistance silicone sealant according to any one of claims 1-8, comprising the following steps: (1) Based on 100 parts by weight of α,ω-dihydroxy polydimethylsiloxane, 100 parts of α,ω-dihydroxy polydimethylsiloxane, 5-40 parts of organosilicon resin, 5-20 parts of dimethyl silicone oil and 70-140 parts of nano-active calcium carbonate are added to a kneader and dehydrated and mixed for 30-300 minutes at 80-150℃ and absolute pressure of 0.001-0.05MPa to obtain a uniform base material I; (2) At room temperature, transfer base material I to a planetary mixer or a high-speed dispersing mixer, add 3-10 parts of alkoxysilane crosslinking agent, and stir for 5-30 minutes under an absolute pressure of 0.005-0.08 MPa and a rotation speed of 10-800 rpm to obtain base material II; (3) Add 1-5 parts of silane coupling agent, 1-5 parts of titanate catalyst and 0.5-5 parts of interface agent to base material II at room temperature, stir and react for 30-120 minutes under absolute pressure of 0.001-0.05MPa and rotation speed of 50-500rpm, and degas to obtain high cyclic load resistant silicone sealant.

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