A weatherable modified silane sealant and a method of making the same

Abstract

The application belongs to the technical field of sealant and particularly relates to a weather-resistant modified silane sealant and a preparation method thereof. The weather-resistant modified silane sealant comprises the following raw materials in parts by weight: 30-50 parts of silane modified polyether resin, 40-80 parts of filler, 10-20 parts of plasticizer, 4-7 parts of weather-resistant agent, 2-5 parts of tackifying promoter, 1-3 parts of thixotropic agent, 1-2 parts of water-removing agent, 1-3 parts of coupling agent and 0.5-1 part of catalyst. The sealant has excellent weather resistance and adhesion, and also has excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of sealant technology, specifically relating to a weather-resistant modified silane sealant and its preparation method. Background Technology

[0002] Silane-modified polyether (MS) sealants, combining the high strength and elasticity of polyurethane sealants with the excellent weather resistance and aging resistance of silicone sealants, have become one of the mainstream choices for high-end sealing materials. However, with the continuous expansion of application areas and increasingly harsh service environments, traditional MS sealants still face some technical bottlenecks.

[0003] MS sealant, when exposed to environmental factors such as ultraviolet radiation, heat, oxygen, and water for extended periods, undergoes photo-oxidative and thermal oxidative degradation of its polymer chains, leading to problems such as yellowing, chalking, cracking, and a sharp decline in mechanical properties. Currently, the common method to delay aging is to add small-molecule antioxidants and ultraviolet absorbers. However, these small-molecule additives are easily lost from the colloid through migration, volatilization, and exudation, not only making it difficult to maintain weather resistance but also potentially contaminating the surfaces of adjacent materials. Furthermore, in the field of prefabricated buildings, release agents often remain on the surface of precast concrete (PC) components, which are porous and alkaline, significantly affecting the wetting and adhesion of the sealant. While this can be addressed by applying a primer, it increases construction steps, costs, and the environmental burden of organic solvents. Therefore, developing a sealant that forms a strong, durable bond with difficult-to-bond substrates such as PC boards and exhibits high weather resistance is a pressing problem for the industry.

[0004] To address the aforementioned issues, existing technologies have made some attempts. For example, CN108048015A improves adhesion by adding epoxy resin, but simple physical blending suffers from poor compatibility and easy phase separation. Furthermore, epoxy resin itself has poor UV aging resistance, potentially becoming a weak point in the material's weather resistance. CN112898934A improves weather durability by adding composite anti-yellowing agents and core-shell alginate microspheres, but its function is limited and it cannot avoid thermal oxidative degradation.

[0005] Therefore, there is an urgent need for a novel molecular design that can fundamentally improve both the weather resistance and adhesion reliability of MS sealant, and to develop a high-performance solution. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the primary objective of this invention is to provide a weather-resistant modified silane sealant with excellent weather resistance, durability and adhesion.

[0007] Another objective of this invention is to provide a method for preparing a weather-resistant modified silane sealant, which has simple steps.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A weather-resistant modified silane sealant, comprising the following raw materials in parts by weight: 30-50 parts silane-modified polyether resin, 40-80 parts filler, 10-20 parts plasticizer, 4-7 parts weather-resistant agent, 2-5 parts tackifier, 1-3 parts thixotropic agent, 1-2 parts dehydrating agent, 1-3 parts coupling agent, and 0.5-1 part catalyst;

[0010] The structural formula of the weather-resistant agent is as follows:

[0011] .

[0012] Preferably, the preparation process of the weather-resistant agent includes the following steps:

[0013] (1) 4-Amino-2,6-di-tert-butylphenol was added to methanol, and bromoacetaldehyde was added at 50-60°C with stirring to carry out the reaction; after the reaction was completed, the mixture was purified to obtain compound 1.

[0014] The structural formula of compound 1 is:

[0015] ;

[0016] (2) The compound 1 was added to acetone, and then 4-(2H-benzotriazol-2-yl)-1,3-benzenediol was added for reflux reaction. After the reaction was complete, the mixture was purified to obtain the weathering agent.

[0017] Preferably, the molar ratio of 4-amino-2,6-di-tert-butylphenol to bromoacetaldehyde in step (1) is 1:(2-2.2); and the reaction time is 0.5-1 h.

[0018] Preferably, in step (2), the molar ratio of compound 1,4-(2H-benzotriazol-2-yl)-1,3-benzenediol is 1:(1.2-1.5); and the reflux reaction time is 10-14 h.

[0019] Preferably, the preparation of the thickening accelerator includes the following steps:

[0020] (a) Methylene butenedioic acid, epichlorohydrin and tetrabutylammonium bromide were mixed and heated to react; then the reaction solution was cooled to 40-50°C, and sodium hydroxide aqueous solution was added and stirred to react. After the reaction was completed, it was purified to obtain intermediate 1.

[0021] The epoxy value of intermediate 1 is 0.60-0.65, and its structural formula is as follows:

[0022] ;

[0023] (b) Intermediate 1, mercaptopropyltrimethoxysilane, and photoinitiator 2959 were added to acetone and mixed. The mixture was stirred and reacted under ultraviolet light. After the reaction was completed, the mixture was purified to obtain the thickening accelerator.

[0024] The tackifier has an epoxy value of 0.35-0.40 and its structural formula is as follows:

[0025] .

[0026] Preferably, in step (a), the ratio of methylene butenedioic acid, epichlorohydrin, tetrabutylammonium bromide, and sodium hydroxide aqueous solution is 1 mmol : (8-10) mmol : (0.025-0.05) mmol : 5 mL; the concentration of the sodium hydroxide aqueous solution is 0.4-0.5 mmol / mL; the heating reaction temperature is 100-110℃, and the time is 25-35 min; the stirring reaction time is 3-5 h.

[0027] Preferably, based on the amount of carbon-carbon double bond functional groups in intermediate 1 obtained in step (a), the molar ratio of intermediate 1, mercaptopropyltrimethoxysilane, and photoinitiator 2959 in step (b) is 1:(1-1.1)l:(0.01-0.0125); the stirring reaction time is 10-20 min.

[0028] Preferably, the filler is selected from one of heavy calcium carbonate, silica, and titanium dioxide; the plasticizer is diisodecyl phthalate or diisononyl phthalate; the dehydrating agent is one of vinyltrimethoxysilane, anhydrous calcium chloride, and calcium oxide; the thixotropic agent is carbon black or polyamide wax; and the coupling agent is one of methyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0029] Preferably, the catalyst is selected from one of dibutyltin dilaurate, monobutyltriisooctanoate, and dihydroxybutyltin chloride; the silane-modified polyether resin is selected from one of trimethoxy-terminated silane-modified polyether resin, dimethoxy-terminated silane-modified polyether resin, and triethoxy-terminated silane-modified polyether resin.

[0030] The preparation method of the above-mentioned weather-resistant modified silane sealant includes the following steps:

[0031] Weigh each raw material according to the formula, mix the silane-modified polyether resin, filler, part of the plasticizer, tackifier, weathering agent, and thixotropic agent evenly, heat to 100-120℃, and knead for 1-2 h under a vacuum of (-0.09~-0.1) MPa; then cool to 40-50℃, add the remaining plasticizer, dehydrating agent, coupling agent, and catalyst, and stir under vacuum for 0.5-1 h to obtain the weather-resistant modified silane sealant.

[0032] The present invention has the following advantages over the prior art:

[0033] 1. The weather-resistant agent molecular structure designed and synthesized in this invention contains both hindered phenolic groups and benzotriazole groups. The hindered phenolic groups can effectively inhibit the oxidative degradation of the polymer matrix by capturing and decomposing peroxide free radicals generated during oxidation; the benzotriazole groups can strongly absorb ultraviolet light and convert it into harmless heat energy, thereby significantly improving the UV aging resistance of the sealant. The two structures work synergistically within the molecule to effectively delay the aging process of the sealant in outdoor environments. In addition, a key ether bond is formed in the weather-resistant agent molecule through a nucleophilic substitution reaction, which not only enhances the stability of the molecular structure, but also introduces a certain degree of steric hindrance and hydrophobicity, giving it excellent compatibility with MS resin, effectively slowing down the migration and precipitation rate of the weather-resistant agent itself, and ensuring the durability of the weather resistance effect.

[0034] 2. This invention uses methylene butenedioic acid as a raw material. The two carboxyl groups in its molecule react with epichlorohydrin to generate intermediate 1, which contains two epoxy groups. Then, the double bonds retained in intermediate 1 react with the mercapto-alkene click reaction of mercaptopropyltrimethoxysilane to obtain a tackifier. The presence of epoxy groups and ether bonds in this tackifier greatly increases the crosslinking density and enhances adhesion to the substrate. Furthermore, the introduced silanoxy groups not only crosslink with the alkoxy groups of the sealant itself, ensuring excellent compatibility, but also, after hydrolysis, form strong Si-O-Si covalent bonds with the hydroxyl groups on the filler and group surfaces, further improving the sealant's weather resistance, durability, and adhesion. Attached Figure Description

[0035] Figure 1 This is the infrared spectrum of intermediate 1 in Embodiment 1 of the present invention;

[0036] Figure 2 This is the infrared spectrum of the thickening accelerator in Example 1 of the present invention. Detailed Implementation

[0037] The technical solution of the present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the reagents or instruments used are all conventional products obtained through commercial channels.

[0038] (I) Implementation Examples

[0039] Example 1

[0040] Example 1 provides a weather-resistant modified silane sealant comprising the following raw materials in parts by weight: 40 parts trimethoxy-terminated silane modified polyether resin, 62 parts heavy calcium carbonate, 17 parts diisodecyl phthalate, 5 parts weather-resistant agent, 4 parts tackifier, 2 parts carbon black, 1.5 parts vinyltrimethoxysilane, 2 parts methyltrimethoxysilane, and 0.8 parts dibutyltin dilaurate.

[0041] The preparation process of the weather-resistant agent includes the following steps:

[0042]

[0043] (1) 4-Amino-2,6-di-tert-butylphenol (CAS: 950-58-3, 10 mmol) was added to methanol (45 mL), and bromoacetaldehyde (CAS: 1620-98-0, 21 mmol) was slowly added dropwise at 55 °C with stirring. After the addition was complete, the reaction was continued for 0.8 h. After the reaction was completed, the methanol and water were removed by concentration under reduced pressure. The crude product was separated and purified by silica gel column chromatography (petroleum ether / ethyl acetate = 30 / 70) to obtain compound 1. The NMR and mass spectrometry results of compound 1 are as follows:

[0044] 1 H NMR (C 16 H 24 BrNO, 400 MHz, d6-DMSO) δ 8.50(t, 1H, N=CH), 7.31 (s, 1H,OH), 6.85 (s, 2H, Ar-H), 4.14(d, 2H, CH2), 1.45 (s, 18H, CH3); HRMS (ESI + ): [M+H] + The result is 326.10, and the value is 326.12.

[0045] (2) Compound 1 (10 mmol) was added to acetone (90 mL), and 4-(2H-benzotriazol-2-yl)-1,3-benzenediol (CAS: 22607-31-4, 14 mmol) was added while stirring. The mixture was then refluxed for 12 h. After the reaction was completed by TLC monitoring, the reaction solution was concentrated to remove acetone, and then 100 mL of ethyl acetate was added. The mixture was washed with water (3 × 30 mL), and the organic phase was collected. The phase was dried, concentrated, and purified by silica gel column chromatography (petroleum ether / ethyl acetate = 50 / 50) to obtain the weathering agent. The NMR and mass spectrometry results of the weathering agent are as follows:

[0046] 1 HNMR (C 28 H 32 N4O3,400MHz,d6-DMSO)δ10.08(s,1H,OH),8.50(t,1H,N=CH),8.05-8.02(m,2H,Ar-H),7.55-7.52(m,2H,Ar-H),7.44(d,1H,A r-H),7.31(s,1H,OH),6.86(s,2H,Ar-H),6.52(d,1H,Ar-H),6.42(s,1H,Ar-H),4.78(d,2H,CH2),1.45(s,18H,CH3);HRMS(ESI + ):[M+H] + The calculation yields 473.25, and the result is 473.24.

[0047] The preparation process of the thickening accelerator is as follows:

[0048]

[0049] (1) Methylene butenedioic acid (CAS: 97-65-4, 20 mmol), epichlorohydrin (CAS: 106-89-8, 170 mmol) and tetrabutylammonium bromide (CAS: 1643-19-2, 0.6 mmol) were mixed and stirred at 105 °C for 30 min. The reaction solution was cooled to 45 °C, and sodium hydroxide aqueous solution (42 mmol, 100 mL) was added. The reaction solution was then stirred for 4 h. The reaction solution was washed with water (5 × 30 mL), and the unreacted epichlorohydrin was concentrated to obtain intermediate 1. The epoxy value of intermediate 1 was determined to be 0.60 by the hydrochloric acid-acetone method.

[0050] (2) Based on the amount of carbon-carbon double bond functional groups in intermediate 1 obtained in step (1), intermediate 1 (n C=C20 mmol), mercaptopropyltrimethoxysilane (CAS: 4420-74-0, 21 mmol), and photoinitiator 2959 (0.23 mmol) were added to acetone (25 mL) and mixed. The mixture was stirred and reacted under UV light (365 nm) for 15 min. The reaction solution was washed with deionized water and saturated sodium chloride in sequence, and then dried and the solvent was removed by rotary evaporation to obtain the thickening accelerator. The epoxy value of the thickening accelerator was determined to be 0.35 by the hydrochloric acid-acetone method.

[0051] Example 1 also provides a method for preparing the above-mentioned weather-resistant modified silane sealant, comprising the following steps:

[0052] Weigh each raw material according to the formula, mix the trimethoxy-terminated silane modified polyether resin, heavy calcium carbonate, 10 parts of diisodecyl phthalate, tackifier, weathering agent, and carbon black evenly, heat to 110°C, and knead for 1.5 h under a vacuum of -0.09 MPa; then cool to 45°C, add the remaining 7 parts of diisodecyl phthalate, vinyltrimethoxysilane, methyltrimethoxysilane, and dibutyltin dilaurate, and stir under vacuum for 0.7 h to obtain the weather-resistant modified silane sealant.

[0053] Example 2

[0054] Example 2 provides a weather-resistant modified silane sealant, comprising the following raw materials in parts by weight: 30 parts dimethoxy-terminated silane modified polyether resin, 40 parts silica, 10 parts diisononyl phthalate, 4 parts weather-resistant agent, 2 parts tackifier, 1 part polyamide wax, 1 part anhydrous calcium chloride, 1 part vinyltrimethoxysilane, and 0.5 parts monobutyltriisooctanoate.

[0055] The preparation process of the weather-resistant agent includes the following steps:

[0056] (1) 4-Amino-2,6-di-tert-butylphenol (10 mmol) was added to methanol (40 mL), and bromoacetaldehyde (20 mmol) was slowly added dropwise at 50 °C with stirring. After the addition was complete, the reaction was continued for 1 h. After the reaction was completed, the methanol and water were removed by concentration under reduced pressure. The crude product was separated and purified by silica gel column chromatography (petroleum ether / ethyl acetate = 30 / 70) to obtain compound 1. The NMR and mass spectrometry results of compound 1 were the same as those in Example 1.

[0057] (2) Compound 1 (10 mmol) was added to acetone (80 mL), and 4-(2H-benzotriazol-2-yl)-1,3-benzenediol (12 mmol) was added while stirring. The mixture was then refluxed for 10 h. After the reaction of the starting materials was completed by TLC monitoring, the reaction solution was concentrated to remove acetone, and then 100 mL of ethyl acetate was added. The mixture was washed with water (3 × 30 mL), and the organic phase was collected. The phase was dried, concentrated, and purified by silica gel column chromatography (petroleum ether / ethyl acetate = 50 / 50) to obtain the weathering agent. The NMR and mass spectrometry results of the weathering agent were the same as those in Example 1.

[0058] The thickening accelerator is prepared by the following process:

[0059] (1) Methylene butenedioic acid (20 mmol), epichlorohydrin (160 mmol) and tetrabutylammonium bromide (0.5 mmol) were mixed and reacted at 100 °C with stirring for 25 min; the reaction solution was cooled to 40 °C, and sodium hydroxide aqueous solution (40 mmol, 100 mL) was added, and then the reaction was stirred for 3 h; the reaction solution was washed with water (5 × 30 mL), and the unreacted epichlorohydrin was concentrated to remove the unreacted epichlorohydrin to obtain intermediate 1; the epoxy value of intermediate 1 was determined to be 0.62 by the hydrochloric acid-acetone method.

[0060] (2) Based on the amount of carbon-carbon double bond functional groups in intermediate 1 obtained in step (1), intermediate 1 (n C=C 20 mmol of mercaptopropyltrimethoxysilane and 0.2 mmol of photoinitiator 2959 were added to acetone (20 mL) and mixed. The mixture was stirred and reacted under ultraviolet light (365 nm) for 10 min. The reaction solution was washed with deionized water and saturated sodium chloride in sequence, and then dried and rotary evaporated to remove the solvent to obtain the thickening accelerator. The epoxy value of the thickening accelerator was determined to be 0.38 by the hydrochloric acid-acetone method.

[0061] Example 2 also provides a method for preparing the above-mentioned weather-resistant modified silane sealant, comprising the following steps:

[0062] Weigh each raw material according to the formula, mix the dimethoxy-terminated silane modified polyether resin, silica, 5 parts of diisononyl phthalate, tackifier, weather resistant agent, and polyamide wax evenly, heat to 100°C, and knead for 1 h under a vacuum of -0.1 MPa; then cool to 40°C, add the remaining 5 parts of diisononyl phthalate, anhydrous calcium chloride, vinyltrimethoxysilane, and monobutyltriisooctanoate, and stir under vacuum for 0.5 h to obtain the weather-resistant modified silane sealant.

[0063] Example 3

[0064] Example 3 provides a weather-resistant modified silane sealant comprising the following raw materials in parts by weight: 50 parts of triethoxy-terminated silane modified polyether resin, 80 parts of titanium dioxide, 20 parts of diisodecyl phthalate, 7 parts of weather-resistant agent, 5 parts of tackifier, 3 parts of carbon black, 2 parts of calcium oxide, 3 parts of vinyltriethoxysilane, and 1 part of dihydroxybutyltin chloride.

[0065] The preparation process of the weather-resistant agent includes the following steps:

[0066] (1) 4-Amino-2,6-di-tert-butylphenol (10 mmol) was added to methanol (50 mL), and bromoacetaldehyde (22 mmol) was slowly added dropwise at 60 °C with stirring. After the addition was complete, the reaction was continued for 1 h. After the reaction was completed, methanol and water were removed by vacuum concentration. The crude product was separated and purified by silica gel column (petroleum ether / ethyl acetate = 30 / 70) to obtain compound 1. The NMR and mass spectrometry results of compound 1 were the same as those in Example 1.

[0067] (2) Compound 1 (10 mmol) was added to acetone (100 mL), and 4-(2H-benzotriazol-2-yl)-1,3-benzenediol (15 mmol) was added while stirring. The mixture was then refluxed for 14 h. After the reaction was completed by TLC monitoring, the reaction solution was concentrated to remove acetone, and then 100 mL of ethyl acetate was added. The mixture was washed with water (3 × 30 mL), and the organic phase was collected. The phase was dried, concentrated, and purified by silica gel column chromatography (petroleum ether / ethyl acetate = 80 / 20) to obtain the weathering agent. The NMR and mass spectrometry results of the weathering agent were the same as in Example 1.

[0068] The thickening accelerator is prepared by the following process:

[0069] (1) Mix methylene butenedioic acid (20 mmol), epichlorohydrin (200 mmol) and tetrabutylammonium bromide (1 mmol) and stir at 110 °C for 35 min; cool the reaction solution to 50 °C, add sodium hydroxide aqueous solution (50 mmol, 100 mL), and then stir for 5 h; wash the reaction solution with water (5 × 30 mL), concentrate to remove unreacted epichlorohydrin, and obtain intermediate 1; determine the epoxy value of intermediate 1 by hydrochloric acid-acetone method to be 0.65;

[0070] (2) Based on the amount of carbon-carbon double bond functional groups in intermediate 1 obtained in step (1), intermediate 1 (n C=C20 mmol of mercaptopropyltrimethoxysilane (22 mmol) and 0.25 mmol of photoinitiator 2959 were added to acetone (30 mL) and mixed. The mixture was stirred and reacted under ultraviolet light (365 nm) for 20 min. The reaction solution was washed with deionized water and saturated sodium chloride in sequence, and then dried and rotary evaporated to remove the solvent to obtain the thickening accelerator. The epoxy value of the thickening accelerator was determined to be 0.4 by the hydrochloric acid-acetone method.

[0071] Example 3 also provides a method for preparing the above-mentioned weather-resistant modified silane sealant, comprising the following steps:

[0072] Weigh each raw material according to the formula, mix the triethoxy-terminated silane modified polyether resin, titanium dioxide, 10 parts of diisodecyl phthalate, tackifier, weathering agent, and carbon black evenly, heat to 120°C, and knead for 1 h under a vacuum of -0.1 MPa; then cool to 50°C, add the remaining 10 parts of diisodecyl phthalate, calcium oxide, vinyltriethoxysilane, and dihydroxybutyltin chloride, and stir under vacuum for 1 h to obtain the weather-resistant modified silane sealant.

[0073] (ii) Comparative Example

[0074] Comparative Example 1

[0075] Comparative Example 1 provides a sealant that differs from Example 1 in that it uses compound 1 from Example 1 instead of the weather-resistant agent, while the rest is the same as Example 1.

[0076] Comparative Example 2

[0077] Comparative Example 2 provides a sealant that differs from Example 1 in that intermediate 1 from Example 1 is used instead of the tackifier, while the rest is the same as Example 1.

[0078] (III) Experimental Examples

[0079] Experimental Example 1

[0080] The intermediate 1 of Example 1 and the thickening accelerator were analyzed by Fourier transform infrared spectroscopy (FT-IR), and the results are as follows: Figure 1-2 As shown.

[0081] Figure 1 This is the infrared spectrum of intermediate 1 in Embodiment 1 of the present invention. Figure 2 This is the infrared spectrum of the thickening accelerator from Example 1 of the present invention. (Observation) Figure 1-2 Know: Figure 1 2987-2850 cm -1 1445cm -1 The absorption peak at 1725 cm⁻¹ is a characteristic peak of the asymmetric stretching vibration and in-plane bending vibration of the CH₂ group.-1 The absorption peak at 1645 cm⁻¹ corresponds to the stretching vibration of the C=O group in the ester group. -1 The absorption peak at 910 cm⁻¹ is due to the stretching vibration of the C=C double bond. -1 The absorption peak at that point is a characteristic peak of the asymmetric stretching vibration of the epoxy group COC. Figure 2 1645 cm -1 The absorption peak disappears at 1093 cm⁻¹. -1 1190 cm -1 815 cm -1 The presence of characteristic peaks for Si-OC and Si-O at the site proves that the grafting of mercaptopropyltrimethoxysilane was successful.

[0082] Experimental Example 2

[0083] The performance of the sealants obtained in Examples 1-3 and Comparative Examples 1-2 was tested, as follows:

[0084] Tensile strength and elongation at break: tested according to GB / T 528-2009 standard, the test results are shown in Table 1;

[0085] 100% tensile modulus: Tested according to GB / T14683-2017 standard, the test results are shown in Table 1;

[0086] Elastic recovery rate: Tested according to GB / T 13477.17-2017 standard, the test results are shown in Table 1;

[0087] UV aging: Tested according to JC / T485-2007 standard, the test results are shown in Table 1;

[0088] At room temperature, the adhesion at constant elongation was tested according to GB / T 13477.10-2017 standard, with a constant elongation of 100%. The test results are shown in Table 1.

[0089] Adhesion at a constant elongation after immersion in water: Tested according to GB / T 13477.11-2017 standard, 100% at a constant elongation, the test results are shown in Table 1;

[0090] Adhesion at a fixed elongation after cold drawing and hot pressing: Tested according to GB / T 13477.13-2019 standard, 100% at a fixed elongation, the test results are shown in Table 1.

[0091] Table 1

[0092]

[0093] As shown in Table 1, the sealant obtained by the present invention has excellent weather resistance and adhesion, as well as excellent mechanical properties.

[0094] Compared to Example 1, the sealant obtained by using Compound 1 instead of the weather-resistant agent in Comparative Example 1 showed reduced weather resistance. Further analysis revealed that the weather-resistant agent molecular structure designed and synthesized in this invention contains both hindered phenolic groups and benzotriazole groups. The hindered phenolic groups can effectively inhibit the oxidative degradation of the polymer matrix by capturing and decomposing peroxide free radicals generated during oxidation; the benzotriazole groups can strongly absorb ultraviolet light and convert it into harmless heat energy, thereby significantly improving the sealant's resistance to ultraviolet aging. The two structures work synergistically within the molecule, effectively delaying the aging process of the sealant in outdoor environments. Furthermore, the weather-resistant agent molecule forms a key ether bond through a nucleophilic substitution reaction, which not only enhances the stability of the molecular structure but also introduces a tert-butyl group that provides steric hindrance and hydrophobicity, giving it excellent compatibility with MS resin and effectively slowing down the migration and precipitation rate of the weather-resistant agent itself, ensuring the durability of its weather-resistant effect.

[0095] Compared to Example 1, the sealant obtained in Comparative Example 2 using Intermediate 1 instead of the tackifier showed reduced adhesion. Further analysis revealed that this invention uses methylene butenedioic acid as a raw material. The two carboxyl groups in its molecule react with epichlorohydrin to generate Intermediate 1, which contains two epoxy groups. Then, the tackifier is prepared by a mercapto-alkene click reaction between the double bonds retained in Intermediate 1 and the mercapto groups of mercaptopropyltrimethoxysilane. The presence of epoxy groups and ether bonds in this tackifier significantly increases the crosslinking density and enhances adhesion to the substrate. Furthermore, the introduced silanoxy groups not only crosslink with the alkoxy groups of the sealant itself, ensuring excellent compatibility, but also, after hydrolysis, form strong Si-O-Si covalent bonds with the fillers and hydroxyl groups on their surfaces, further improving the sealant's weather resistance, durability, and adhesion.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A weather-resistant modified silane sealant, characterized in that, The raw materials include the following parts by weight: 30-50 parts silane-modified polyether resin, 40-80 parts filler, 10-20 parts plasticizer, 4-7 parts weathering agent, 2-5 parts tackifier, 1-3 parts thixotropic agent, 1-2 parts dehydrating agent, 1-3 parts coupling agent, and 0.5-1 part catalyst. The structural formula of the weather-resistant agent is as follows: ； The tackifier has an epoxy value of 0.35-0.40 and its structural formula is as follows: 。 2. The weather-resistant modified silane sealant according to claim 1, characterized in that, The preparation process of the weather-resistant agent includes the following steps: (1) 4-Amino-2,6-di-tert-butylphenol was added to methanol, and bromoacetaldehyde was added at 50-60°C with stirring to carry out the reaction; after the reaction was completed, the mixture was purified to obtain compound 1. The structural formula of compound 1 is: ； (2) The compound 1 was added to acetone, and then 4-(2H-benzotriazol-2-yl)-1,3-benzenediol was added for reflux reaction. After the reaction was complete, the mixture was purified to obtain the weathering agent.

3. The weather-resistant modified silane sealant according to claim 2, characterized in that, The molar ratio of 4-amino-2,6-di-tert-butylphenol to bromoacetaldehyde in step (1) is 1:(2-2.2); the reaction time is 0.5-1 h.

4. The weather-resistant modified silane sealant according to claim 2, characterized in that, In step (2), the molar ratio of compound 1,4-(2H-benzotriazol-2-yl)-1,3-benzenediol is 1:(1.2-1.5); the reflux reaction time is 10-14 h.

5. The weather-resistant modified silane sealant according to claim 1, characterized in that, The preparation of the thickening accelerator includes the following steps: (a) Methylene butenedioic acid, epichlorohydrin and tetrabutylammonium bromide were mixed and heated to react; then the reaction solution was cooled to 40-50°C, and sodium hydroxide aqueous solution was added and stirred to react. After the reaction was completed, it was purified to obtain intermediate 1. The epoxy value of intermediate 1 is 0.60-0.65, and its structural formula is as follows: ； (b) Intermediate 1, mercaptopropyltrimethoxysilane, and photoinitiator 2959 were added to acetone and mixed. The mixture was stirred and reacted under ultraviolet light. After the reaction was completed, the mixture was purified to obtain the thickening accelerator.

6. The weather-resistant modified silane sealant according to claim 5, characterized in that, In step (a), the ratio of methylene butenedioic acid, epichlorohydrin, tetrabutylammonium bromide, and sodium hydroxide aqueous solution is 1 mmol : (8-10) mmol : (0.025-0.05) mmol : 5 mL; the concentration of the sodium hydroxide aqueous solution is 0.4-0.5 mmol / mL; the heating reaction temperature is 100-110℃, and the time is 25-35 min; the stirring reaction time is 3-5 h.

7. The weather-resistant modified silane sealant according to claim 5, characterized in that, Based on the amount of carbon-carbon double bond functional groups in intermediate 1 obtained in step (a), the molar ratio of intermediate 1, mercaptopropyltrimethoxysilane, and photoinitiator 2959 in step (b) is 1:(1-1.1):(0.01-0.0125); the stirring reaction time is 10-20 min.

8. The weather-resistant modified silane sealant according to claim 1, characterized in that, The filler is selected from one of heavy calcium carbonate, silicon dioxide, and titanium dioxide; the plasticizer is diisodecyl phthalate or diisononyl phthalate; the dehydrating agent is one of vinyltrimethoxysilane, anhydrous calcium chloride, and calcium oxide; the thixotropic agent is carbon black or polyamide wax; and the coupling agent is one of methyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

9. The weather-resistant modified silane sealant according to claim 1, characterized in that, The catalyst is selected from one of dibutyltin dilaurate, monobutyltriisooctanoate, and dihydroxybutyltin chloride; the silane-modified polyether resin is selected from one of trimethoxy-terminated silane-modified polyether resin, dimethoxy-terminated silane-modified polyether resin, and triethoxy-terminated silane-modified polyether resin.

10. A method for preparing the weather-resistant modified silane sealant according to any one of claims 1-9, characterized in that, Includes the following steps: Weigh each raw material according to the stated weight proportions, mix the silane-modified polyether resin, filler, part of the plasticizer, tackifier, weathering agent, and thixotropic agent evenly, heat to 100-120℃, and knead for 1-2 hours under a vacuum of (-0.09~-0.1) MPa; then cool to 40-50℃, add the remaining plasticizer, dehydrating agent, coupling agent, and catalyst, and stir under vacuum for 0.5-1 hours to obtain the weather-resistant modified silane sealant.

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