A method for synthesizing high-performance moisture-curing silicone resin and its application

Abstract

This invention relates to the field of organosilicon resin preparation technology, specifically to a method for synthesizing a high-performance moisture-curing organosilicon resin and its application. The preparation steps of the organosilicon resin are as follows: Step 1, adding an epoxy monomer and 2-vinylpyridine to a solvent, then adding an initiator to obtain a mixture; Step 2, adding the organosilicon monomer to the solvent, adding a composite catalyst, and stirring to react, obtaining an organosilicon prepolymer; Step 3, at room temperature, adding a modified filler to the mixture, stirring to react under inert gas protection, then adding the organosilicon prepolymer, copolymerizing, and distilling under reduced pressure to obtain the organosilicon resin. The prepared organosilicon resin exhibits excellent mechanical properties, high tensile strength, large elongation at break, excellent tear strength, water impermeability, good bonding strength, and high curing efficiency, with short surface drying and hard drying times. It possesses both mechanical strength and flexibility, as well as reliable waterproofing and adhesion.

Description

Technical Field

[0001] This invention relates to the field of organosilicon resin preparation technology, and more specifically, to a method for synthesizing high-performance moisture-curing organosilicon resin and its application. Background Technology

[0002] Moisture-curing silicone resins are a class of functional materials that are cross-linked by environmental moisture and have wide applications in building sealing, electronic packaging, industrial protection, and other fields. However, traditional moisture-curing silicone resins still face the following core problems in practical applications: (1) Traditional alkoxysilane systems rely on moisture in the air to complete the hydrolysis-condensation reaction, but the curing speed is significantly affected by humidity and temperature. In low humidity environments (such as dry areas or winter), the curing time is prolonged or even incomplete cross-linking is not possible, resulting in low construction efficiency; (2) Conventional moisture-curing resins have low cross-linking density, which makes it difficult for the hardness, tensile strength and tear resistance of the cured material to meet the requirements of high-end applications. At the same time, long-term exposure to ultraviolet rays, salt spray or chemical media can easily cause yellowing, embrittlement or surface powdering, affecting service life; (3) Moisture-curing silicone resins generally have weak adhesion to non-silicone substrates and require primers or complex surface treatments (such as sandblasting or plasma activation) to achieve reliable bonding, which increases the complexity and cost of the process. In addition, uneven dispersion of fillers or insufficient interfacial bonding can easily lead to coating delamination or cracking. Summary of the Invention

[0003] To address the technical problems mentioned in the background section, this invention provides a method for synthesizing high-performance moisture-curing silicone resins and their applications, optimizing the overall performance of traditional moisture-curing silicone resins and providing a new path for the green and high-performance development of silicone functional materials.

[0004] This invention provides a method for synthesizing high-performance moisture-curing silicone resin, employing the following technical solution:

[0005] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0006] Step 1: Add the epoxy monomer and 2-vinylpyridine to the solvent, then add the initiator, stir until homogeneous, and obtain a mixture.

[0007] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30-40℃, add the composite catalyst, stir and react for 2-4 hours to obtain the organosilicon prepolymer;

[0008] Step 3: At room temperature, add the modified filler to the mixture, heat to 40-50℃ under inert gas protection, stir and react for 1-2 hours, then add the organosilicon prepolymer, stir evenly, heat to 60-80℃, copolymerize for 3-4 hours, and distill under reduced pressure to obtain the high-performance moisture-curing organosilicon resin.

[0009] Preferably, the epoxy monomer is one or more of 3,4-epoxycyclohexyl methacrylate, allyl glycidyl ether, and glycidyl methacrylate.

[0010] Preferably, the mass ratio of the epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 18-25:10-12:60-80:0.2-0.5.

[0011] Preferably, the solvent is a mixture of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7-9:1-3.

[0012] Preferably, the organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime groups in a mass ratio of 10-15:5-8:2-5.

[0013] Preferably, the organosilicon monomer containing the oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 8-10:1-3.

[0014] Preferably, the mass ratio of the organosilicon monomer, solvent and composite catalyst is 20-30:60-80:0.1-0.2.

[0015] Preferably, the composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3-8:1-2.

[0016] Preferably, the mass ratio of the mixture, modified filler, and organosilicon prepolymer is 30-40:10-20:50-60.

[0017] Preferably, the modified filler is prepared by dispersing the nanofiller in a polyvinyl alcohol aqueous solution, ultrasonically treating it for 10-30 min, magnetically stirring it at 60-80℃ for 1-2 h, and drying it to obtain the hydroxylated filler; adding the hydroxylated filler to a mercaptosilane coupling agent ethanol solution, adjusting the pH to 4-6 with acetic acid, heating it to 50-80℃, stirring it under nitrogen protection for 2-4 h, filtering, washing, and drying it at 60-80℃ for 4-6 h to obtain the modified filler.

[0018] Preferably, the mercaptosilane coupling agent is one or more selected from γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane.

[0019] Preferably, the nanofiller is one or more of nano-silica, nano-silicon carbide, and nano-boron nitride.

[0020] This invention also provides a high-performance moisture-curing silicone resin prepared by the above method for use in the coatings field.

[0021] In summary, the present invention has the following beneficial effects:

[0022] This invention selects epoxy monomers and 2-vinylpyridine as polymerizing monomers. The epoxy groups in the epoxy monomers can act as active crosslinking points during subsequent copolymerization and curing, which can increase the rigidity of the copolymer segments. Furthermore, the synergistic crosslinking of epoxy groups and organosilicon prepolymers can form a denser network structure, reducing the penetration paths of solvent molecules or water molecules. Meanwhile, the pyridine ring and vinyl segments of 2-vinylpyridine can provide a certain degree of flexibility. The combination of the two can balance the rigidity and flexibility of the resin. Moreover, the polar groups of the pyridine ring and the polar structure of the epoxy group can improve the adhesion of the resin to polar substrates (such as metals and glass). During the wet curing process, the weakly basic groups of the pyridine ring in 2-vinylpyridine can catalyze the hydrolysis of alkoxy groups in organosilicon prepolymers to generate silanol groups, accelerating the condensation crosslinking reaction.

[0023] This invention uses methyltrimethoxysilane, perfluorooctyltriethoxysilane, and organosilicon monomers containing oxime groups as monomers for synthesizing organosilicon resins. Methyltrimethoxysilane has a relatively fast hydrolysis rate, providing initial strength to the resin, while the oxime group has a delayed cross-linking effect. The oxime group hydrolyzes slowly in moisture, releasing ketoximes and generating silanol groups. Its reaction rate is lower than that of methoxy and tetra(4-methyl-2-pentanone oxime). Silanes provide four oxime groups, resulting in high crosslinking density but slow reaction. Vinyl tributanone oxime silanes, with their vinyl groups, can participate in free radical copolymerization, and the three oxime groups provide a moderate crosslinking rate, avoiding the uneven curing and cracking caused by single oxime silanes. In this silicone resin, methyltrimethoxysilane provides rapid initial crosslinking, and silicone monomers containing oxime groups fill network defects through delayed crosslinking. Furthermore, perfluorooctyltriethoxysilane is selected, which, through the low surface energy and chemical stability of the fluorocarbon segments and the crosslinking ability of silane oxy groups, endows the resin with excellent waterproof and antifouling properties. Its compound system with methyltrimethoxysilane and oxime silanes, through functional complementarity, overcomes the performance limitations of single silane monomers.

[0024] In this invention, a silane coupling agent containing thiol groups is used to treat the nanofiller. The thiol groups can undergo a thiol-ene click reaction with the double bonds in 2-vinylpyridine and 3,4-epoxycyclohexylmethacrylate in the mixture to form stable CS bonds. Simultaneously, after hydrolysis, the silanoxy groups condense with the hydroxyl groups on the surface of nano-silica to form Si-O-Si covalent bonds. Through the bridging structure, the interfacial bonding strength between the filler and the resin matrix is ​​significantly improved, reducing stress concentration. Furthermore, the mixture and the modified nano-silica first undergo a partial click reaction between the thiol groups and double bonds, allowing the filler to be uniformly dispersed in the polymer matrix. When the organosilicon prepolymer is added, its silanol groups can further react with the epoxy groups or residual double bonds in the mixture, further polymerizing the organosilicon network and the pre-dispersed filler, thereby improving the overall strength and toughness. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments.

[0026] The 3,4-epoxycyclohexyl methacrylate used in the embodiments and comparative examples of this invention was purchased from Wuhan Smike Biotechnology Co., Ltd.; methyltrimethoxysilane (item number: YJ-68) was purchased from Shandong Yuanjin New Materials Co., Ltd.; perfluorooctyltriethoxysilane was purchased from Wuhan Smike Biotechnology Co., Ltd.; tetrakis(4-methyl-2-pentanone oxime)silane (industrial grade) was purchased from Jingzhou Yinjie Chemical Co., Ltd.; vinyltributylone oxime silane was purchased from Yunsheng Chemical (Shandong) Co., Ltd.; nano silica was purchased from Shijiazhuang Huihe Yongsheng Nanotechnology Co., Ltd.; polyvinyl alcohol was purchased from Jinan Xinling Chemical Technology Co., Ltd.; and γ-mercaptopropyltrimethoxysilane was purchased from Wuhan Smike Biotechnology Co., Ltd.

[0027] Examples 1-3 provide a method for synthesizing high-performance moisture-curing silicone resins and their applications.

[0028] Example 1

[0029] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0030] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 18:10:60:0.2, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0031] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30℃, add the composite catalyst, and stir for 2 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 10:5:2. The organosilicon monomer containing oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 8:1. The mass ratio of organosilicon monomer, solvent and composite catalyst is 20:60:0.1. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7:3. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3:1.

[0032] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 40°C under inert gas protection, stir and react for 1 hour, then add organosilicon prepolymer, stir evenly, control the stirring speed at 100 rpm, heat to 60°C, copolymerize for 3 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica and organosilicon prepolymer is 30:10:50.

[0033] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 5 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 1:5, and ultrasonically treated for 10 min at a power of 100 W and a frequency of 40 kHz. The mixture was then magnetically stirred at 60 °C for 1 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 2 wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 3:10. Acetic acid was added to adjust the pH to 4, and the temperature was raised to 50 °C. The mixture was stirred for 2 h under nitrogen protection at a stirring speed of 200 rpm, filtered, washed, and dried at 60 °C for 4 h to obtain modified nano-silica.

[0034] Example 2

[0035] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0036] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 22:11:70:0.4, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0037] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 35℃, add the composite catalyst, and stir for 3 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 12:7:4. The organosilicon monomer containing oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 9:2. The mass ratio of organosilicon monomer, solvent and composite catalyst is 25:70:0.15. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 8:2. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 5:1.5.

[0038] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 45°C under inert gas protection, stir and react for 1.5 hours, then add organosilicon prepolymer, stir evenly, control the stirring speed at 150 rpm, heat to 70°C, copolymerize for 3.5 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica, and organosilicon prepolymer is 35:15:55.

[0039] The modified nano-silica was prepared as follows: Nano-silica was dispersed in an 8 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 2:7, and ultrasonically treated for 20 min at an ultrasonic power of 110 W and an ultrasonic frequency of 50 kHz. The mixture was then magnetically stirred at 70 °C for 1.5 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 4 wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 4:11. Acetic acid was added to adjust the pH to 5, and the temperature was raised to 65 °C. The mixture was stirred for 3 h under nitrogen protection at a stirring speed of 300 rpm, filtered, washed, and dried at 70 °C for 5 h to obtain modified nano-silica.

[0040] Example 3

[0041] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0042] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 25:12:80:0.5, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0043] Step 2: Add the organosilicon monomers to the solvent, stir evenly, heat to 40℃, add the composite catalyst, and stir for 4 hours to obtain the organosilicon prepolymer. The organosilicon monomers are composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomers containing oxime groups in a mass ratio of 15:8:5. The organosilicon monomers containing oxime groups are composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 10:3. The mass ratio of organosilicon monomers, solvent and composite catalyst is 30:80:0.2. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 9:1. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 8:2.

[0044] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 50°C under inert gas protection, stir and react for 2 hours, then add organosilicon prepolymer, stir evenly, control the stirring speed at 200 rpm, heat to 80°C, copolymerize for 4 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica, and organosilicon prepolymer is 40:20:60.

[0045] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 10wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 3:10. The mixture was ultrasonically treated for 30 min at a power of 120 W and a frequency of 60 kHz. The mixture was then magnetically stirred at 80℃ for 2 h and dried to obtain a hydroxylated filler. The hydroxylated filler was then added to a 5wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 5:12. Acetic acid was added to adjust the pH to 6. The mixture was heated to 80℃ and stirred for 4 h under nitrogen protection at a stirring speed of 400 rpm. The mixture was then filtered, washed, and dried at 80℃ for 6 h to obtain the modified nano-silica.

[0046] Comparative Example 1

[0047] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0048] Step 1: Add 2-vinylpyridine to the solvent, then add azobisisobutyronitrile, stir until homogeneous to obtain a mixture, wherein the mass ratio of 2-vinylpyridine, solvent and azobisisobutyronitrile is 28:60:0.2;

[0049] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30℃, add the composite catalyst, and stir for 2 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 10:5:2. The organosilicon monomer containing oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 8:1. The mass ratio of organosilicon monomer, solvent and composite catalyst is 20:60:0.1. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7:3. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3:1.

[0050] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 40°C under inert gas protection, stir and react for 1 hour, then add organosilicon prepolymer, stir evenly, control the stirring speed at 100 rpm, heat to 60°C, copolymerize for 3 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica and organosilicon prepolymer is 30:10:50.

[0051] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 5 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 1:5, and ultrasonically treated for 10 min at a power of 100 W and a frequency of 40 kHz. The mixture was then magnetically stirred at 60 °C for 1 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 2 wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 3:10. Acetic acid was added to adjust the pH to 4, and the temperature was raised to 50 °C. The mixture was stirred for 2 h under nitrogen protection at a stirring speed of 200 rpm, filtered, washed, and dried at 60 °C for 4 h to obtain modified nano-silica.

[0052] Comparative Example 2

[0053] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0054] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 18:10:60:0.2, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0055] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30℃, add the composite catalyst, stir and react for 2 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 10:2. The organosilicon monomer containing oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 8:1. The mass ratio of organosilicon monomer, solvent and composite catalyst is 20:60:0.1. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7:3. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3:1.

[0056] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 40°C under inert gas protection, stir and react for 1 hour, then add organosilicon prepolymer, stir evenly, control the stirring speed at 100 rpm, heat to 60°C, copolymerize for 3 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica and organosilicon prepolymer is 30:10:50.

[0057] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 5 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 1:5, and ultrasonically treated for 10 min at a power of 100 W and a frequency of 40 kHz. The mixture was then magnetically stirred at 60 °C for 1 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 2 wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 3:10. Acetic acid was added to adjust the pH to 4, and the temperature was raised to 50 °C. The mixture was stirred for 2 h under nitrogen protection at a stirring speed of 200 rpm, filtered, washed, and dried at 60 °C for 4 h to obtain modified nano-silica.

[0058] Comparative Example 3

[0059] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0060] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 18:10:60:0.2, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0061] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30°C, add the composite catalyst, and stir for 2 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 10:5:2. The organosilicon monomer containing oxime group is tetrakis(4-methyl-2-pentanone oxime)silane. The mass ratio of organosilicon monomer, solvent and composite catalyst is 20:60:0.1. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7:3. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3:1.

[0062] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 40°C under inert gas protection, stir and react for 1 hour, then add organosilicon prepolymer, stir evenly, control the stirring speed at 100 rpm, heat to 60°C, copolymerize for 3 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica and organosilicon prepolymer is 30:10:50.

[0063] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 5 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 1:5, and ultrasonically treated for 10 min at a power of 100 W and a frequency of 40 kHz. The mixture was then magnetically stirred at 60 °C for 1 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 2 wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 3:10. Acetic acid was added to adjust the pH to 4, and the temperature was raised to 50 °C. The mixture was stirred for 2 h under nitrogen protection at a stirring speed of 200 rpm, filtered, washed, and dried at 60 °C for 4 h to obtain modified nano-silica.

[0064] Comparative Example 4

[0065] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0066] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 18:10:60:0.2, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0067] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30°C, add the composite catalyst, and stir for 2 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 10:5:2. The organosilicon monomer containing oxime group is vinyltributylone oxime silane. The mass ratio of organosilicon monomer, solvent and composite catalyst is 20:60:0.1. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7:3. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3:1.

[0068] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 40°C under inert gas protection, stir and react for 1 hour, then add organosilicon prepolymer, stir evenly, control the stirring speed at 100 rpm, heat to 60°C, copolymerize for 3 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica and organosilicon prepolymer is 30:10:50.

[0069] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 5 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 1:5, and ultrasonically treated for 10 min at a power of 100 W and a frequency of 40 kHz. The mixture was then magnetically stirred at 60 °C for 1 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 2 wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 3:10. Acetic acid was added to adjust the pH to 4, and the temperature was raised to 50 °C. The mixture was stirred for 2 h under nitrogen protection at a stirring speed of 200 rpm, filtered, washed, and dried at 60 °C for 4 h to obtain modified nano-silica.

[0070] Comparative Example 5

[0071] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0072] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 18:10:60:0.2, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0073] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30℃, add the composite catalyst, and stir for 2 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 10:5:2. The organosilicon monomer containing oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 8:1. The mass ratio of organosilicon monomer, solvent and composite catalyst is 20:60:0.1. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7:3. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3:1.

[0074] Step 3: At room temperature, add modified nano-silica to the mixture, heat to 40°C under inert gas protection, stir and react for 1 hour, then add organosilicon prepolymer, stir evenly, control the stirring speed at 100 rpm, heat to 60°C, copolymerize for 3 hours, and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica and organosilicon prepolymer is 30:10:50.

[0075] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 5 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 1:5, and ultrasonically treated for 10 min at a power of 100 W and a frequency of 40 kHz. The mixture was then magnetically stirred at 60 °C for 1 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 2 wt% γ-aminopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 3:10. Acetic acid was added to adjust the pH to 4, and the temperature was raised to 50 °C. The mixture was stirred for 2 h under nitrogen protection at a stirring speed of 200 rpm, filtered, washed, and dried at 60 °C for 4 h to obtain modified nano-silica.

[0076] Comparative Example 6

[0077] A method for synthesizing a high-performance moisture-curing silicone resin includes the following preparation steps:

[0078] Step 1: Add epoxy monomer and 2-vinylpyridine to solvent, then add azobisisobutyronitrile, stir evenly to obtain a mixture, wherein the mass ratio of epoxy monomer, 2-vinylpyridine, solvent and azobisisobutyronitrile is 18:10:60:0.2, and the epoxy monomer is 3,4-epoxycyclohexyl methacrylate.

[0079] Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30℃, add the composite catalyst, and stir for 2 hours to obtain the organosilicon prepolymer. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime group in a mass ratio of 10:5:2. The organosilicon monomer containing oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 8:1. The mass ratio of organosilicon monomer, solvent and composite catalyst is 20:60:0.1. The solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7:3. The composite catalyst is composed of dibutyltin dilaurate and triethylamine in a mass ratio of 3:1.

[0080] Step 3: At room temperature, add modified nano-silica and organosilicon prepolymer to the mixture. Under inert gas protection, heat to 40°C and stir for 1 hour. Then heat to 60°C and copolymerize for 3 hours. Control the stirring speed at 100 rpm and distill under reduced pressure to obtain high-performance moisture-curing organosilicon resin. The mass ratio of the mixture, modified nano-silica, and organosilicon prepolymer is 30:10:50.

[0081] The modified nano-silica was prepared as follows: Nano-silica was dispersed in a 5 wt% polyvinyl alcohol aqueous solution, with a solid-liquid ratio of 1:5, and ultrasonically treated for 10 min at a power of 100 W and a frequency of 40 kHz. The mixture was then magnetically stirred at 60 °C for 1 h and dried to obtain hydroxylated filler. The hydroxylated filler was then added to a 2 wt% γ-mercaptopropyltrimethoxysilane ethanol solution, with a solid-liquid ratio of 3:10. Acetic acid was added to adjust the pH to 4, and the temperature was raised to 50 °C. The mixture was stirred for 2 h under nitrogen protection at a stirring speed of 200 rpm, filtered, washed, and dried at 60 °C for 4 h to obtain modified nano-silica.

[0082] Performance testing

[0083] The high-performance moisture-curing silicone resins prepared in Examples 1-3 and Comparative Examples 1-6 were tested for tensile strength, elongation at break, impermeability, bond strength, and curing time in accordance with the requirements of the national standard GB / T16777-2008 "Test Methods for Waterproof Coatings for Buildings".

[0084] The test results are shown in Table 1.

[0085] Table 1. Performance parameters of the high-performance moisture-curing silicone resins prepared in Examples 1-3 and Comparative Examples 1-6

[0086]

[0087] As shown in Table 1, the high-performance moisture-curing silicone resin prepared by this invention possesses excellent mechanical properties. This high-performance moisture-curing silicone resin exhibits high tensile strength, large elongation at break, excellent tear strength, water impermeability, good bonding strength, and high curing efficiency, with short surface drying and hard drying times. Its comprehensive performance is well-balanced, possessing both mechanical strength and flexibility, as well as reliable waterproofing and adhesion. It is convenient to apply and suitable for scenarios requiring high performance and construction efficiency.

[0088] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for synthesizing a high-performance moisture-curing silicone resin, characterized in that, The preparation steps include the following: Step 1: Add the epoxy monomer and 2-vinylpyridine to the solvent, then add the initiator, stir until homogeneous, and obtain a mixture. Step 2: Add the organosilicon monomer to the solvent, stir evenly, heat to 30-40℃, add the composite catalyst, stir and react for 2-4 hours to obtain the organosilicon prepolymer; Step 3: At room temperature, add the modified filler to the mixture, heat to 40-50℃ under inert gas protection, stir and react for 1-2 hours, then add the organosilicon prepolymer, stir evenly, heat to 60-80℃, copolymerize for 3-4 hours, and distill under reduced pressure to obtain the high-performance moisture-curing organosilicon resin. The organosilicon monomer is composed of methyltrimethoxysilane, perfluorooctyltriethoxysilane and organosilicon monomer containing oxime groups in a mass ratio of 10-15:5-8:2-5. The organosilicon monomer containing the oxime group is composed of tetrakis(4-methyl-2-pentanone oxime)silane and vinyltributylone oxime silane in a mass ratio of 8-10:1-3.

2. The method for synthesizing high-performance moisture-curing silicone resin according to claim 1, characterized in that, The epoxy monomer is one or more of 3,4-epoxycyclohexyl methacrylate, allyl glycidyl ether, and glycidyl methacrylate.

3. The method for synthesizing high-performance moisture-curing silicone resin according to claim 1, characterized in that, The mass ratio of the epoxy monomer to 2-vinylpyridine is 18-25:10-12.

4. The method for synthesizing the high-performance moisture-curing silicone resin according to claim 1, characterized in that, The solvent is a compound of dimethyl carbonate and propylene glycol methyl ether acetate in a volume ratio of 7-9:1-3.

5. The method for synthesizing high-performance moisture-curing silicone resin according to claim 1, characterized in that, The mass ratio of the mixture, modified filler, and organosilicon prepolymer is 30-40:10-20:50-60.

6. The method for synthesizing the high-performance moisture-curing silicone resin according to claim 1, characterized in that, The modified filler is prepared by: The nanofiller was dispersed in a polyvinyl alcohol aqueous solution, sonicated for 10-30 min, magnetically stirred at 60-80℃ for 1-2 h, and dried to obtain the hydroxylated filler. The hydroxylated filler was added to an ethanol solution of mercaptosilane coupling agent, the pH was adjusted to 4-6 with acetic acid, the temperature was raised to 50-80℃, and the reaction was stirred for 2-4 h under nitrogen protection. The mixture was then filtered, washed, and dried at 60-80℃ for 4-6 h to obtain the modified filler.

7. The method for synthesizing the high-performance moisture-curing silicone resin according to claim 6, characterized in that, The mercaptosilane coupling agent is one or more of γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane.

8. The application of a high-performance moisture-curing silicone resin synthesized using the synthesis method of any one of claims 1-7 in coatings.

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