Mildew-proof silicone sealant with high curing rate and high adhesive force and preparation method thereof

Abstract

This application relates to the field of sealants, and particularly to a high-curing-rate, high-adhesion, mildew-resistant silicone sealant and its preparation method. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant comprises a base adhesive, plasticizer, combined crosslinking agent, reinforcing filler, catalyst, combined mildew inhibitor, coupling agent, and combined reinforcing agent. The silicone sealant prepared in this application achieves a good balance between rapid surface drying and deep curing in terms of curing performance, adapting to various construction environments. In terms of adhesion performance, it exhibits excellent initial bond strength and long-lasting adhesion to common substrates such as glass, metal, and ceramics. It also possesses good water resistance and anti-aging properties, maintaining a long-term sealing effect. Furthermore, it retains a simple preparation process, facilitating industrial production. Its comprehensive performance better meets the application needs of kitchen and bathroom sealing and building sealing applications.

Description

Technical Field

[0001] This application relates to the field of sealants, and in particular to a high-curing-rate, high-adhesion, mildew-resistant silicone sealant and its preparation method. Background Technology

[0002] Silicone sealants, as an important building sealing material, are widely used in building curtain walls, door and window installations, interior decoration, and bathroom facilities due to their excellent weather resistance, high and low temperature resistance, and good elastic recovery. Especially in humid environments such as kitchens, bathrooms, and basements, sealants not only need to fill joints and provide waterproofing, but also must resist mold growth to prevent material aging, aesthetic degradation, and indoor air pollution caused by mold. Therefore, mold-resistant silicone sealants have become a key focus of research and application in this field, typically achieved by adding organotin or organonitrogen antifungal agents to the sealant.

[0003] However, existing anti-mildew silicone sealants often face the dilemma of balancing curing rate and adhesive performance in practical applications. While traditional de-alcoholized or deoxime-based silicone sealants offer good overall performance, their curing process relies on moisture penetration from the air, resulting in slow deep curing, especially in low-temperature, high-humidity, or poorly ventilated environments. This significantly prolongs surface drying and complete curing times, severely impacting construction efficiency and project progress. To improve curing rate, some existing technologies attempt to increase catalyst dosage or change the type of crosslinking agent, but this often leads to side effects. For example, excessively rapid surface drying may result in surface skinning without internal curing, or the reaction may be too vigorous, generating bubbles that weaken the sealant's density and final strength.

[0004] More importantly, in pursuit of rapid curing, the adhesive strength of existing anti-mildew sealants often declines to varying degrees. High-speed curing can lead to excessive shrinkage stress at the interface, resulting in insufficient wetting between the sealant and the substrate (such as glass, aluminum alloy, ceramic, or plastic), thus creating microscopic defects and reducing adhesive strength. Furthermore, the large amount of anti-mildew additives added to achieve the anti-mildew effect can sometimes cause compatibility issues with the base adhesive or crosslinking system, or even migrate to the adhesive interface, forming a weak boundary layer and further deteriorating adhesive performance. This insufficient adhesive strength, under dynamic loads or thermal expansion and contraction, can easily lead to seal failure, delamination, and cracking, creating a risk of leakage. Summary of the Invention

[0005] In summary, existing anti-mold silicone sealants generally suffer from slow curing rates, affecting construction efficiency, or they sacrifice bond strength while increasing curing speed. Furthermore, the addition of anti-mold additives often exacerbates the instability of the adhesive interface, making it difficult to simultaneously meet the comprehensive performance requirements of rapid curing, high adhesion, and long-lasting anti-mold properties. Therefore, developing a silicone sealant that can achieve rapid curing to meet the needs of efficient construction, maintain excellent bond strength, and possess reliable anti-mold functionality has become a pressing technical challenge for the industry.

[0006] To achieve the above objectives, this application provides the following technical solution: The first aspect of this application provides a mildew-resistant silicone sealant with high curing rate and high adhesion. By weight, its raw material scheme includes: 50-70 parts of base adhesive, 20-30 parts of plasticizer, 6-10 parts of combined crosslinking agent, 8-12 parts of reinforcing filler, 0.005-0.01 parts of catalyst, 4-6 parts of combined mildew inhibitor, 1-1.5 parts of coupling agent, and 3-6 parts of combined reinforcing agent.

[0007] Preferably, the mass ratio of the matrix adhesive, plasticizer, and combined crosslinking agent is (5.5~6.5):(2.2~2.7):(0.7~1).

[0008] Preferably, the mass ratio of the matrix adhesive, plasticizer, and combined crosslinking agent is (6~6.5):(2.3~2.6):(0.8~1).

[0009] Preferably, the matrix adhesive is α,ω-dihydroxypolydimethylsiloxane.

[0010] Preferably, the viscosity of the matrix adhesive is 4000~7000 mPa·s at 25°C.

[0011] Preferably, the viscosity of the matrix adhesive is 4000~5000 mPa·s at 25°C.

[0012] Preferably, the plasticizer is α,ω-di(trimethylsiloxy)polydimethylsiloxane or methylphenyl silicone oil.

[0013] Preferably, the plasticizer is α,ω-di(trimethylsiloxy)polydimethylsiloxane.

[0014] Preferably, the viscosity of the α,ω-bis(trimethylsiloxy)polydimethylsiloxane is 1000~1500 mPa·s at 25°C.

[0015] Preferably, the viscosity of the α,ω-bis(trimethylsiloxy)polydimethylsiloxane is 1000~1200 mPa·s at 25°C.

[0016] Preferably, the combined crosslinking agent is a combination of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane and butyl acetate.

[0017] Preferably, the mass ratio of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane and butyl acetate is (4~6):(0.8~1.5):(4~6).

[0018] Preferably, the mass ratio of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane and butyl acetate is (4~5):(1~1.2):(4~5).

[0019] Preferably, the reinforcing filler is a combination of fumed silica and titanium dioxide.

[0020] Preferably, the mass ratio of the fumed silica to titanium dioxide is (8~11):(1~3).

[0021] Preferably, the mass ratio of fumed silica to titanium dioxide is (9~10):(1.5~2).

[0022] Preferably, the specific surface area of ​​the fumed silica is 200~240 m². 2 / g.

[0023] Preferably, the average particle size of the fumed silica is 10~40 nm.

[0024] Preferably, the average particle size of the fumed silica is 10~30 nm.

[0025] Preferably, the titanium dioxide has an average particle size of 200~400nm.

[0026] Preferably, the titanium dioxide has an average particle size of 200~300nm.

[0027] Preferably, the catalyst is at least one selected from dibutyltin diacetate, dibutyltin diacetate, and stannous octoate.

[0028] Preferably, the catalyst is dibutyltin diacetate.

[0029] Preferably, the combined antifungal agent is a combination of trichloroethylene and acrylonitrile.

[0030] Preferably, the mass ratio of trichloroethylene to acrylonitrile is (3~5):(1~2).

[0031] Preferably, the mass ratio of trichloroethylene to acrylonitrile is (4~5):(1~1.5).

[0032] This application uses α,ω-dihydroxypolydimethylsiloxane and α,ω-di(trimethylsiloxy)polydimethylsiloxane as the base polymer to provide crosslinking active sites for the sealant system to ensure the curing reaction and adjust the viscosity and flexibility of the system. Together, they create a matrix environment suitable for crosslinking reaction and dispersion of combined antifungal agents. The crosslinking agent and the combined antifungal agents trichloroethylene and acrylonitrile form a co-solubilized system, and the antifungal agent molecules are uniformly embedded in the crosslinking network. This can effectively inhibit mold growth and reduce the melting point of the crosslinking agent through intermolecular interactions, thereby preventing low-temperature crystallization, while not interfering with the crosslinking reaction activity, thus improving the overall performance.

[0033] Preferably, the coupling agent is at least one selected from γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethoxysilane.

[0034] Preferably, the coupling agent is γ-aminopropyltriethoxysilane and / or γ-glycidoxypropyltrimethoxysilane.

[0035] Preferably, the coupling agent is γ-aminopropyltriethoxysilane.

[0036] Preferably, the combined reinforcing agent is a combination of dipropylene glycol dibenzoate, hydrogenated rosin methyl ester and rosin glyceryl ester.

[0037] Preferably, the mass ratio of dipropylene glycol dibenzoate, hydrogenated rosin methyl ester and rosin glyceryl ester is (2~3):(1~1.5):(0.4~0.8).

[0038] Preferably, the mass ratio of dipropylene glycol dibenzoate, hydrogenated rosin methyl ester and rosin glyceryl ester is (2~2.5):(1~1.2):(0.5~0.7).

[0039] By combining reinforcing agents to lower the glass transition temperature of the colloidal system with dipropylene glycol dibenzoate molecular chain segments, the mobility of molecular chains is enhanced, allowing the colloid to spread and wet the substrate surface more fully during curing. Furthermore, the polar carboxylic acid ester groups in the molecular structure of rosin migrate to the interfacial region during the colloid curing process, providing an adhesive strength enhancement effect. The combined effect of these three factors gives the sealant system good molecular freedom, providing channels for the interfacial migration of tackifying components, further improving adhesion. Thus, while maintaining the flexibility of the colloid itself, it maintains excellent bonding strength, long-term adhesion stability, and excellent elastic recovery.

[0040] Preferably, the mass ratio of the matrix adhesive, the combined antifungal agent, and the combined reinforcing agent is (5.5~6.5):(0.5~0.6):(0.4~0.6).

[0041] Preferably, the mass ratio of the matrix adhesive, the combined antifungal agent, and the combined reinforcing agent is (6~6.5):(0.5~0.56):(0.4~0.5).

[0042] The second aspect of this application provides a method for preparing the above-mentioned high-curing-rate, high-adhesion, mildew-resistant silicone sealant, specifically including the following steps: S1: Add the matrix adhesive and plasticizer into the planetary mixer, turn on the mixer, heat up and dehydrate and stir under vacuum of ≥0.095MPa. Separately, take the combined crosslinking agent and mildew inhibitor and stir and mix them evenly at room temperature to form a homogeneous premixed liquid. S2: Mix all the materials obtained in step S1 with the combined reinforcing agent, and simultaneously add the reinforcing filler and silane coupling agent. Stir under a vacuum of ≥0.09 MPa to ensure that all components are fully and evenly dispersed. S3: Add the remaining raw materials to the planetary mixer, fill with nitrogen for protection, continue mixing under vacuum, and package the material in a sealed container after discharge.

[0043] Preferably, the preparation method of the high-curing-rate, high-adhesion, mildew-resistant silicone sealant specifically includes the following steps: S1: Add the matrix adhesive and plasticizer into the planetary mixer, turn on the mixer, heat to 110~115℃, dehydrate and stir for 45~50min under vacuum degree ≥0.095 MPa. Separately, take the combined crosslinking agent and mildew inhibitor and stir and mix them evenly at room temperature to form a homogeneous premix. S2: Mix all the materials obtained in step S1 with the combined reinforcing agent, and simultaneously add the reinforcing filler and silane coupling agent. Stir for 30-35 minutes under vacuum ≥0.09 MPa to ensure that all components are fully and evenly dispersed. S3: Add the remaining raw materials to the planetary mixer, fill with nitrogen for protection, and continue mixing under vacuum for 20-25 minutes. After discharging, package in a sealed container to obtain the final product.

[0044] The beneficial effects and application advantages of this application are as follows: 1. The silicone sealant prepared in this application effectively solves the problems of easy crystallization and poor storage stability of traditional anti-mildew silicone sealants during low-temperature storage, significantly improving the product's lifespan. In terms of curing performance, it achieves a good balance between rapid surface drying and deep curing, and can adapt to various construction environments. In terms of adhesion performance, it exhibits excellent initial adhesion strength and long-lasting adhesion to common substrates such as glass, metal, and ceramics. It also has good water resistance and anti-aging ability, can maintain the sealing effect for a long time, and retains a simple preparation process, making it easy to industrialize. Its comprehensive performance can better meet the application needs of kitchen and bathroom and building sealing fields.

[0045] 2. The α,ω-dihydroxypolydimethylsiloxane and α,ω-di(trimethylsiloxy)polydimethylsiloxane used in this application are compounded as the base polymer, providing crosslinking active sites for the sealant system and adjusting the viscosity and flexibility of the system. Under their combined action, a matrix environment suitable for crosslinking reaction and dispersion of combined antifungal agents is constructed. Furthermore, the crosslinking agent and the compounded antifungal agents trichloroethylene and acrylonitrile form a co-solubilized system, and the antifungal agent molecules are uniformly embedded in the crosslinking network, which can effectively inhibit the growth of mold and improve the overall performance.

[0046] 3. This application uses a combination of reinforcing agents to lower the glass transition temperature of the colloidal system by using dipropylene glycol dibenzoate molecular chain segments, thereby enhancing the mobility of the molecular chains. This allows the colloid to spread and wet the substrate surface more fully during the curing process. Furthermore, the polar carboxylic acid ester groups in the molecular structure of rosin migrate to the interface region during the colloid curing process, providing enhanced adhesion and increasing the molecular freedom of the system. As a result, while maintaining the flexibility of the colloid itself, it maintains excellent bonding strength, long-lasting adhesion stability, and excellent elastic recovery. Attached Figure Description

[0047] Figure 1 This is a photograph of the anti-mildew silicone sealant with high curing rate and high adhesion obtained in Example 1 of this application. Detailed Implementation

[0048] In the following specific embodiments, unless otherwise specified, the sources / preparation methods of some raw materials are as follows: α,ω-Dihydroxypolydimethylsiloxane, Jiangxi Blue Star Spark Organosilicon, China.

[0049] α,ω-Di(trimethylsiloxy)polydimethylsiloxane, Jiangxi Blue Star Starfire Organosilicon, China.

[0050] Methyltriacetoxysilane, di-tert-butoxydiacetoxysilane, Hubei Xinlantian New Materials, China.

[0051] Example 1 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 62.5 parts base adhesive, 24 parts plasticizer, 8.8 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 4.3 parts combined reinforcing agent.

[0052] The matrix adhesive is α,ω-dihydroxypolydimethylsiloxane with a viscosity of 5000 mPa·s at 25℃.

[0053] The plasticizer is α,ω-di(trimethylsiloxy)polydimethylsiloxane with a viscosity of 1000 mPa·s and a temperature of 25℃.

[0054] The combined crosslinking agent is a combination of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane and butyl acetate in a mass ratio of 4.5:1:4.5.

[0055] The reinforcing filler is a combination of fumed silica and titanium dioxide in a mass ratio of 10:1.5.

[0056] The specific surface area of ​​fumed silica is 220 m². 2 / g, with an average particle size of 20nm; titanium dioxide has an average particle size of 230nm.

[0057] The catalyst is dibutyltin diacetate; the coupling agent is γ-aminopropyltriethoxysilane.

[0058] The combined mildew inhibitor is a combination of trichloroethylene and acrylonitrile in a mass ratio of 4.5:1.5.

[0059] The combined reinforcing agent is a combination of dipropylene glycol dibenzoate, hydrogenated rosin methyl ester and rosin glyceryl ester, in a mass ratio of 2.4:1:0.6.

[0060] A method for preparing the above-mentioned high-curing-rate, high-adhesion, mildew-resistant silicone sealant specifically includes the following steps: S1: Add the matrix adhesive and plasticizer into the planetary mixer, turn on the mixer, heat to 110°C, and dehydrate and stir for 50 minutes under a vacuum of ≥0.095 MPa. Separately, take the combined crosslinking agent and mildew inhibitor and stir and mix them evenly at room temperature of 25°C to form a homogeneous premix. S2: Mix all the materials obtained in step S1 with the combined reinforcing agent, and simultaneously add the reinforcing filler and silane coupling agent. Stir for 30 minutes under a vacuum of ≥0.09 MPa to ensure that all components are fully and evenly dispersed. S3: Add the remaining raw materials to the planetary mixer, fill with nitrogen for protection, and continue mixing under vacuum for 22 minutes. After discharging, package in a sealed container to obtain the final product.

[0061] The actual product of the high-curing-rate, high-adhesion, mildew-resistant silicone sealant prepared in this embodiment is shown below. Figure 1 As shown.

[0062] Example 2 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 58 parts base adhesive, 22 parts plasticizer, 7.2 parts combined crosslinking agent, 9.2 parts reinforcing filler, 0.005 parts catalyst, 5.2 parts combined mildew inhibitor, 1.1 parts coupling agent, and 4 parts combined reinforcing agent.

[0063] The combined crosslinking agent is a combination of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane and butyl acetate in a mass ratio of 6:1.2:5.

[0064] The above are the only differences between this embodiment and Embodiment 1; all other aspects are the same.

[0065] Example 3 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 65 parts base adhesive, 26.5 parts plasticizer, 9.5 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 4.3 parts combined reinforcing agent.

[0066] The combined mildew inhibitor is a combination of trichloroethylene and acrylonitrile in a mass ratio of 5:1.2.

[0067] The above are the only differences between this embodiment and Embodiment 1; all other aspects are the same.

[0068] Comparative Example 1 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 62.5 parts base adhesive, 30 parts plasticizer, 3.2 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 4.3 parts combined reinforcing agent.

[0069] The above are the only differences between this comparative example and Example 1; all other aspects are the same.

[0070] Comparative Example 2 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 70 parts base adhesive, 24 parts plasticizer, 8.8 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 1.5 parts combined reinforcing agent.

[0071] The above are the only differences between this comparative example and Example 1; all other aspects are the same.

[0072] Comparative Example 3 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 62.5 parts base adhesive, 24 parts plasticizer, 8.8 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 4.3 parts combined reinforcing agent.

[0073] The combined crosslinking agent is a combination of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane and butyl acetate in a mass ratio of 5:0.2:4.8.

[0074] The above are the only differences between this comparative example and Example 1; all other aspects are the same.

[0075] Comparative Example 4 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 62.5 parts base adhesive, 24 parts plasticizer, 8.8 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 4.3 parts combined reinforcing agent.

[0076] The combined mildew inhibitor is a combination of trichloroethylene and acrylonitrile in a mass ratio of 5.5:0.5.

[0077] The above are the only differences between this comparative example and Example 1; all other aspects are the same.

[0078] Comparative Example 5 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 62.5 parts base adhesive, 24 parts plasticizer, 8.8 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 4.3 parts combined reinforcing agent.

[0079] The combined reinforcing agent is a combination of dipropylene glycol dibenzoate, hydrogenated rosin methyl ester and rosin glyceryl ester, in a mass ratio of 3.6:0.2:0.2.

[0080] The above are the only differences between this comparative example and Example 1; all other aspects are the same.

[0081] Comparative Example 6 A high-curing-rate, high-adhesion, mildew-resistant silicone sealant, by weight, comprises the following raw materials: 62.5 parts base adhesive, 24 parts plasticizer, 8.8 parts combined crosslinking agent, 9.8 parts reinforcing filler, 0.005 parts catalyst, 5.5 parts combined mildew inhibitor, 1.2 parts coupling agent, and 4.3 parts combined reinforcing agent.

[0082] The combined reinforcing agent is a combination of dipropylene glycol dibenzoate, hydrogenated rosin methyl ester and rosin glyceryl ester in a mass ratio of 0.5:2:1.5.

[0083] The above are the only differences between this comparative example and Example 1; all other aspects are the same.

[0084] Performance testing 1. Surface drying time: At a temperature of 23±2℃ and a relative humidity of 50±5%, the sealant sample is extruded and filled into a mold of specified size. The surface is smoothed, a polyethylene film is placed on the sample surface, and a weight is used to press it down. The sample is checked every 5 minutes, and the time when no more adhesive residue remains on the film is recorded. The average of 10 surface drying times (min) is recorded in Table 1.

[0085] 2. Mold Prevention: For the examples and comparative examples, 50mm × 50mm × 6mm samples of the sealant were prepared and cured for 28 days at 23±2℃ and 50±5% relative humidity. Standard mold strains of *Aspergillus niger* and *Aspergillus flavus* were selected, and 1×10⁻⁶ samples were prepared. 6 A CFU / mL spore suspension mixture was prepared. The sample was placed in a petri dish containing malt extract agar, and 0.5 mL of the spore mixture was added and evenly spread on the sample surface. The sample was then incubated in a constant temperature and humidity chamber at 28±1℃ and relative humidity ≥95% for 28 days. Observations were made every 7 days. The mold growth area and spore formation were compared with the standard spectrum. Grade 0: No growth and no spore formation of either fungus on the sample surface; Grade 1: At least one fungus growth area <10%, spores dispersed, single colony diameter ≤5mm; Grade 2: At least one fungus growth area 10%~30%; Grade 3: At least one fungus growth area >30%. The anti-mold grade was recorded in Table 1.

[0086] 3. Mechanical properties: The sealant prepared in the examples and comparative examples was used to prepare dumbbell-shaped specimens. The specimens were cured under standard conditions for 28 days and placed in the fixture of an electronic universal testing machine. The tensile speed was set to 500 mm / min and the specimens were continuously stretched until they broke. The maximum tensile strength and elongation at break were recorded. Ten specimens were tested in each group, and the average value was recorded in Table 1.

[0087] 4. Tensile bond strength at 23℃: A standard aluminum plate with dimensions of 50mm×50mm×12mm was selected. The sealant was bonded between the surfaces of two parallel aluminum plates with a bond thickness of 2mm. The plates were cured for 28 days at 23±2℃ and 50%±5% relative humidity. The specimens were then mounted on the fixture of an electronic universal testing machine and loaded with a tensile speed of 5mm / min. The maximum bond tensile strength and bond failure area at the point of specimen failure were recorded. The average of 10 tests was recorded in Table 1.

[0088] 5. Elastic recovery rate: Sealant samples prepared in the examples and comparative examples were cured at 23±2℃ and 50% relative humidity for 28 days. The sample width was then stretched to 200% of its original width and held under tension for 24 hours before being released. The recovered width was measured and compared with the width before the test. The average of 10 elastic recovery rate tests was recorded in Table 1. Table 1 Performance Test Results Analysis of Test Results: Examples 1-3 of this application, by employing the basic polymer scheme and combined reinforcing agent scheme defined in this application, provide crosslinking active sites for the sealant system and adjust the system viscosity and flexibility. Through their combined action, a matrix environment suitable for crosslinking reaction and dispersion of the combined antifungal agent is constructed, achieving an improvement in overall performance. Furthermore, they provide adhesion enhancement, maintaining excellent bond strength, long-lasting adhesion stability, and excellent elastic recovery. Comparative Examples 1-6, however, employ different technical solutions than those in this application, resulting in a significant decrease in the effectiveness of their raw materials in the system, thus leading to a decline in the performance of the final product.

[0089] The above description is the preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principles described in this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A mildew-resistant silicone sealant with high curing speed and high adhesion, characterized in that: The raw material formula, by weight, includes: 50-70 parts of matrix adhesive, 20-30 parts of plasticizer, 6-10 parts of combined crosslinking agent, 8-12 parts of reinforcing filler, 0.005-0.01 parts of catalyst, 4-6 parts of combined mildew inhibitor, 1-1.5 parts of coupling agent, and 3-6 parts of combined reinforcing agent. The matrix adhesive is α,ω-dihydroxypolydimethylsiloxane with a viscosity of 4000~7000 mPa·s and a temperature of 25℃. The combined crosslinking agent is a combination of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane and butyl acetate, in a mass ratio of (4~6):(0.8~1.5):(4~6). The combined antifungal agent is a combination of trichloroethylene and acrylonitrile, with a mass ratio of (3~5):(1~2).

2. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 1, characterized in that: The mass ratio of the matrix adhesive, plasticizer, and combined crosslinking agent is (5.5~6.5):(2.2~2.7):(0.7~1).

3. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 2, characterized in that: The plasticizer is α,ω-di(trimethylsiloxy)polydimethylsiloxane or methylphenyl silicone oil.

4. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 3, characterized in that: The reinforcing filler is a combination of fumed silica and titanium dioxide, with a mass ratio of (8~11):(1~3).

5. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 4, characterized in that: The specific surface area of ​​fumed silica is 200~240m². 2 / g, with an average particle size of 10~40nm; the titanium dioxide has an average particle size of 200~400nm.

6. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 5, characterized in that: The coupling agent is at least one selected from γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethoxysilane.

7. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 6, characterized in that: The combined reinforcing agent is a combination of dipropylene glycol dibenzoate, hydrogenated rosin methyl ester and rosin glyceryl ester, in a mass ratio of (2~3):(1~1.5):(0.4~0.8).

8. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 7, characterized in that: The coupling agent is γ-aminopropyltriethoxysilane and / or γ-glycidoxypropyltrimethoxysilane.

9. The high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to claim 8, characterized in that: The mass ratio of the matrix adhesive, the combined antifungal agent, and the combined reinforcing agent is (5.5~6.5):(0.5~0.6):(0.4~0.6).

10. A method for preparing a high-curing-rate, high-adhesion, mildew-resistant silicone sealant according to any one of claims 1 to 9, characterized in that: Specifically, the following steps are included: S1: Add the matrix adhesive and plasticizer into the planetary mixer, turn on the mixer, heat up and dehydrate and stir under vacuum of ≥0.095 MPa. Separately, take the combined crosslinking agent and mildew inhibitor and stir and mix them evenly at room temperature to form a homogeneous premixed liquid. S2: Mix all the materials obtained in step S1 with the combined reinforcing agent, and simultaneously add the reinforcing filler and silane coupling agent. Stir under a vacuum of ≥0.09 MPa to ensure that all components are fully and evenly dispersed. S3: Add the remaining raw materials to the planetary mixer, fill with nitrogen for protection, continue mixing under vacuum, and package the material in a sealed container after discharge.

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