Terminal-functionalized polysiloxanes, their preparation methods and applications

Abstract

This invention discloses an end-functionalized polysiloxane, its preparation method, and its applications, belonging to the field of organosilicon materials technology. The aim is to introduce polyalkoxysilanes containing heteroatom groups (N, O, etc.) into the ends of polysiloxanes via hydrosilylation reactions, thereby achieving end-group modification of polysiloxanes to obtain functionalized polysiloxanes. This polymer is then used in alcohol-based sealants. Compared to hydroxyl-terminated 107 sealant, this end-functionalized polysiloxane exhibits better storage stability. Furthermore, the heteroatom groups at the polymer's ends, such as amino, epoxy, and ether bonds, all contribute to improved adhesion to various substrates, resulting in stronger bonds. In addition, the end-functionalized groups also facilitate more uniform dispersion of the polysiloxane and fillers, improving the overall performance of the sealant.

Description

Technical Field

[0001] This invention relates to the field of organosilicon materials technology, and in particular to a polysiloxane with heteroatom alkoxy-terminated ends, a method for preparing the same, and the application of the polymer in alcohol-based sealants. Background Technology

[0002] De-alcoholized room temperature vulcanizing silicone rubber (RTV) is an important polymer material with wide applications in construction, electronics, automobiles and other fields due to its good weather resistance, high and low temperature resistance, electrical insulation and environmental friendliness.

[0003] Traditional dealcoholized silicone rubber is typically prepared using α,ω-dihydroxy polydimethylsiloxane (trade name 107 glue) as the base rubber, combined with alkoxysilane crosslinking agents, organotitanium catalysts, and reinforcing fillers. However, dealcoholized silicone rubber prepared using 107 glue as the base rubber presents several key problems in actual production and application: First, the silanol groups in 107 glue interact with the organotitanium catalyst, easily leading to a "viscosity peak" phenomenon during production, making mixing difficult and even causing equipment damage; second, the high reactivity of silanol groups results in poor product storage stability, typically with a shelf life of no more than 3 months; furthermore, 107 glue easily forms hydrogen bonds with the hydroxyl groups on the surface of inorganic fillers (such as silica), making it difficult for the fillers to disperse uniformly, resulting in a "structuring" problem. Structuring refers to the physical crosslinking network formed between the silanol groups on the surface of the inorganic fillers and the terminal hydroxyl groups of the polysiloxane molecular chains through hydrogen bonds, causing the rubber to harden and lose processability; finally, 107 glue has limited adhesion to certain substrates (such as metals and plastics), requiring the addition of a large amount of coupling agent.

[0004] To address the aforementioned issues, researchers attempted to treat 107 adhesive with alkoxy-terminated polysiloxanes. Existing technologies primarily employ two methods for preparing alkoxy-terminated polysiloxanes: condensation and addition. Condensation involves the reaction of hydroxyl-terminated polysiloxanes with alkoxysilanes in the presence of a catalyst (such as organic amines or alkali metal hydroxides). However, this method often suffers from problems such as incomplete catalyst removal, leading to residual impurities in the product and affecting storage stability. For example, CN104558612B uses organic amine salts as catalysts, which, while improving the end-capping rate, inevitably leaves a residual ammonia odor in the product; CN104231275B uses alkali metal catalysts, but the neutralization process is complex and it is difficult to prepare high-viscosity products. Addition methods involve hydrosilylation reactions, reacting vinyl-terminated polysiloxanes with hydrogen-containing silanes, or hydrogen-containing end-terminated polysiloxanes with vinyl silanes. For example, CN104479132B uses dimethyldichlorosilane to react with 107 glue and then with alkoxysilane, which is a complex process and produces hydrogen chloride as a byproduct. CN110878142A uses vinyl silicone oil and alkoxyhydrosilane to prepare alkoxy-terminated polysiloxane through hydrosilylation under platinum catalysis. Although the effect is better, the product lacks specific functional groups to improve the adhesive properties.

[0005] While existing alkoxy-terminated polysiloxanes have addressed the storage stability and viscosity peak issues of 107 silicone rubber to some extent, they often lack sufficient functional groups to improve adhesion to various substrates and are also insufficient to significantly improve compatibility and dispersibility with fillers. Especially in demanding applications such as electronic packaging and photovoltaic modules, silicone rubber requires excellent adhesion, long-term storage stability, and comprehensive mechanical properties.

[0006] Therefore, developing a functionalized polysiloxane that possesses both high storage stability and excellent adhesion and filler compatibility is of great significance for improving the overall performance of dealcoholized silicone rubber. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a polysiloxane with alkoxy-terminated heteroatom groups, its preparation method, and its application. This polymer introduces polyalkoxysilanes containing heteroatom groups (such as N, O, etc.) at both ends of the polysiloxane through a hydrosilylation reaction, exhibiting excellent storage stability, adhesive properties, and compatibility with fillers.

[0008] Another object of the present invention is to provide a de-alcoholized silicone rubber with alkoxy-terminated polysiloxane containing heteroatomic groups as the base rubber and a method for preparing the same.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] An end-functionalized polysiloxane, which is capped with an alkoxy group containing a heteroatom, has the following structural formula:

[0011]

[0012] Among them, R 1 R 2 R 3 R is an alkyl, alkoxy, or halogen atom containing 1 to 12 carbon atoms. 1 R 2 R 3 They can be the same or different;

[0013] Each R 4 and R 5 Independently alkyl, aryl, vinyl, H, or combinations thereof, R 4 R 5 They can be the same or different;

[0014] It is a group or combination thereof containing epoxy, ether, alkane, amino, oxygen-containing heterocycle, nitrogen-containing heterocycle or H atom. These groups can form chemical bonds or strong interactions with the substrate surface during the curing process of silicone rubber, which can significantly improve the adhesion performance.

[0015] p is 0-10, n is 1-100, m is 1-1200, and q is 0-300;

[0016] The weight-average molecular weight (M) of the polysiloxane w The values ​​range from 100 to 1,000,000 g / mol, including but not limited to 1,000 g / mol, 10,000 g / mol, 50,000 g / mol, 100,000 g / mol, 200,000 g / mol, 500,000 g / mol, 1,000,000 g / mol, etc.

[0017] In some embodiments of the present invention, m can be selected as 200-1200, p and n are both 1, and q is 0;

[0018] In some embodiments of the present invention, m can be selected as 200-1200, p and n are both 1, and q is 200-300;

[0019] In some embodiments of the present invention, p can be selected as 1-10, n as 1-100, m as 1-1200, and q as 1-300.

[0020] This invention also provides a method for preparing the above-mentioned end-functionalized polysiloxane, comprising the following steps:

[0021] 1) A vinyl-terminated polysiloxane and a hydrogen-containing silane are mixed at a vinyl to silane molar ratio of 1:(1.05-1.3), a platinum catalyst is added, and the mixture is reacted at 60-110℃ for 1-4 hours to obtain a hydrogen-terminated polysiloxane; the reaction formula is as follows:

[0022]

[0023] Hydrogen-terminated polysiloxane

[0024] 2) The hydrogen-terminated polysiloxane and the vinyl-functionalized siloxane are mixed in a molar ratio of 1:(1.05-1.3) of silane-hydrogen bonds to vinyl groups, and a platinum catalyst is added. The mixture is reacted at 70-110°C for 1-3 hours to obtain the terminally functionalized polysiloxane. The reaction formula is as follows:

[0025]

[0026] Terminal-functionalized polysiloxanes

[0027] In the method for preparing terminally functionalized polysiloxanes, the general structural formula of the terminally vinyl polysiloxane is as follows:

[0028]

[0029] Each R 4 and R 5 Independently alkyl, aryl, vinyl, H, or combinations thereof, R 4 R 5 They can be the same or different; m is 1-1200, and q is 0-300.

[0030] In the method for preparing terminal-functionalized polysiloxanes, the hydrogen-containing silane is one or more of 1,1,3,3-tetramethyldisiloxane and hydrogen-terminated polydimethylsiloxane, with the following general structural formula:

[0031] n is 1-100.

[0032] In the method for preparing end-functionalized polysiloxanes, the general structural formula of the vinyl-containing functionalized siloxane is as follows:

[0033]

[0034] Preferably, R 1 R 2 R 3 R is an alkyl, alkoxy, or halogen atom containing 1 to 12 carbon atoms. 1 R 2 R 3 They can be the same or different;

[0035] It is a group containing an epoxy, ether, alkane, amino, oxygen-containing heterocycle, nitrogen-containing heterocycle, H atom, or a combination thereof;

[0036] p is 0-10.

[0037] Preferably, the method for synthesizing the vinyl-containing functionalized siloxane includes the following steps:

[0038] Step 1: Add base to silane coupling agent containing primary amine, toluene and haloalkene, stir and mix under nitrogen protection, react at 40-80℃ for 4-6 h, cool and let stand, filter and evaporate solvent to obtain intermediate M;

[0039] , where X is a halogen atom;

[0040] Step 2: Add toluene, heteroatom-containing haloalkanes and base to intermediate M obtained in Step 1, and react at a temperature of 40-80℃ for 4-6 h to obtain vinyl-containing functionalized alkoxysilane F.

[0041]

[0042] In the synthesis of vinyl-containing functionalized siloxanes, optionally, the molar ratio of the silane coupling agent containing a primary amine, the haloalkene, and the heteroatom-containing haloalkane is 1:(1.1~1.3):(1.2~1.4), preferably 1:1.2:1.3 mol.

[0043] In the method for synthesizing vinyl-containing functionalized siloxanes, the silane coupling agent containing a primary amine is any one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, and 3-aminopropyltris(methoxyethoxyethoxy)silane.

[0044] In the synthesis method of vinyl-containing functionalized siloxanes, the haloalkene is a haloalkene with a p-value of 0-10, such as halogenated ethylene, halogenated propylene, halogenated butene, halogenated hexene, halogenated heptene, halogenated decene, etc., and the halogen atom X includes fluorine, chlorine, bromine, and iodine. More specifically, the haloalkene is any one or more of 3-chloro-1-propene, 4-chloro-1-butene, 6-chloro-1-hexene, 7-chloro-1-heptene, 8-chloro-1-octene, 3-bromo-1-propene, 4-bromo-1-butene, 6-bromo-1-hexene, 7-bromo-1-heptene, 8-bromo-1-octene, 3-iodopropene, 4-iodo-1-butene, and 6-iodo-1-hexene.

[0045] In the method for synthesizing vinyl-containing functionalized siloxanes, the heteroatom-containing haloalkanes include, but are not limited to, halogenated derivatives of epoxides (such as propylene oxide, butane oxide, hexane oxide, etc.), chlorinated derivatives of ethylene glycol diethyl ether, halodioxanes (such as 2-(chloromethyl)-1,3-dioxane, etc.), halomorpholines (such as N-(3-chloropropyl)morpholine, etc.), and N,N-dimethyl-3-chloropropylamine. More specifically, the heteroatom-containing haloalkanes are any one or more of the following: 3-chloro-1,2-epoxypropane, 4-chloro-1,2-epoxybutane, 2-(3-chloropropyl)epoxyethylene, 6-chloro-1,2-epoxyhexane, 3-bromo-1,2-epoxypropane, 4-bromo-1,2-epoxybutane, 2-(3-bromopropyl)epoxyethylene, 6-bromo-1,2-epoxyhexane, 3-iodine-1,2-epoxypropane, 4-iodine-1,2-epoxybutane; 6-iodine-1,2-epoxyhexane, 2-(2-ethoxyethoxy)ethylbromide, 2-(bromomethyl)-1,4-dioxane, 3-bromo-N,N-dimethylpropyl-1-amine, and 4-(3-bromopropyl)morpholine.

[0046] In the synthesis of vinyl-containing functionalized siloxanes, toluene is used as the solvent and a base as the catalyst. The base catalyst is an inorganic base such as sodium carbonate, potassium carbonate, or cesium carbonate, or an organic base such as triethylamine, N,N-diisopropylethylamine, diazabicyclohexane, or pyridine.

[0047] Additionally, vinyl-functionalized alkoxysilanes F can be exemplified by the organosilicon compounds shown below, wherein F1-F8 and F'2 are all made from aminopropyltrialkoxysilane, while F9 is made from aminopropyltrichlorosilane, F'1 is made from aminopropyltrimethylsilane, F1-F9 and F'1 all use heteroatom-containing haloalkanes as raw materials, F'2 uses haloalkanes in a straight chain, and F'3 is a commercially available material:

[0048]

[0049] In the method for preparing terminal-functionalized polysiloxanes, the platinum catalyst is chloroplatinic acid, platinum-vinylsiloxane complex, platinum-divinyltetramethyldisiloxane complex, or platinum-vinylcyclic complex, and the amount used is 1-100 ppm of the total mass of the reactants.

[0050] The end-functionalized polysiloxane is used as a base material in de-alcoholized sealants.

[0051] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0052] 1. The end-group functionalization of polysiloxanes is achieved through hydrosilylation, avoiding the acid or base catalyst residues and neutralization steps in the traditional condensation method. The process is simple, the product has high purity, and excellent storage stability.

[0053] 2. Introducing polyalkoxysilanes containing heteroatom groups (such as amino, epoxy, ether bonds, etc.) at the end of polysiloxanes significantly improves the adhesion performance of polymers to various substrates (such as metals, glass, ceramics, plastics, etc.) without the need to add a large amount of coupling agent.

[0054] 3. The presence of heteroatom groups enhances the compatibility of polysiloxanes with inorganic fillers (such as silica, calcium carbonate, and alumina), resulting in more uniform dispersion, avoiding "structural" problems, and improving the mechanical and processing properties of silicone rubber.

[0055] 4. The alcohol-free silicone rubber prepared using the alkoxy-terminated polysiloxane containing heteroatomic groups as the base rubber avoids the "viscosity peak" phenomenon in the production process, has good process performance, and excellent storage stability.

[0056] 5. The preparation method of the present invention does not require high temperature and high pressure, the reaction conditions are mild, the process is simple, it is suitable for industrial production, and has good application prospects. Detailed Implementation

[0057] The following provides a detailed description of the embodiments of the present invention: The embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0058] All raw materials used in the examples are industrial-grade polymers, purified before use, and have no other special requirements.

[0059] Raw material preparation: Preparation of vinyl-containing functionalized siloxane small molecules

[0060] Step 1: Add triethylamine (1.5 mol) to a mixture of aminopropyltrimethoxysilane or aminopropyltrimethylsilane or aminopropyltrichlorosilane (1 mol), toluene (100 mL), and haloolefin (1.2 mol). Stir and mix under nitrogen protection, heat to 70°C and react for 4 hours. Cool down and let stand, filter and evaporate the solvent to obtain intermediate M.

[0061] Step 2: Toluene (100 mL), heteroatom-containing haloalkanes (1.3 mol), and triethylamine (1.5 mol) were added to intermediate M obtained in Step 1, and the mixture was heated to 70 °C and reacted for 4 hours to obtain vinyl-containing functionalized siloxane small molecules F1~F9. and .in This is a commercially available product that can be purchased directly. The structure of the product was confirmed using 1H NMR and infrared spectroscopy.

[0062] The specific raw materials for the preparation of vinyl-containing functionalized siloxane small molecules are shown in Table 1.

[0063] Table 1. Raw materials for vinyl-containing functionalized siloxane small molecules

[0064] Product code Amino organosilicon Halogenated olefins heteroatom-containing haloalkanes F1 aminopropyltrimethoxysilane Chloride epichlorohydrin F2 aminopropyltrimethoxysilane Chloride Epoxyhexane F3 aminopropyltrimethoxysilane Hexyl bromide epichlorohydrin F4 aminopropyltrimethoxysilane Hexyl bromide Chlorinated derivatives of ethylene glycol diethyl ether F5 aminopropyltrimethoxysilane Hexyl bromide 2-(chloromethyl)-1,3-dioxane F6 aminopropyltrimethoxysilane Hexyl bromide N-(3-Chloropropyl)morpholine F7 aminopropyltrimethoxysilane Hexyl bromide N,N-Dimethyl-3-chloropropane F8 aminopropyl dimethoxymethylsilane Hexyl bromide epichlorohydrin F9 aminopropyltrichlorosilane Hexyl bromide epichlorohydrin aminopropyltrimethylsilane Hexyl bromide epichlorohydrin aminopropyltrimethoxysilane Hexyl bromide 1-Chlorobutane

[0065] Example 1: Preparation of terminal-functionalized polysiloxanes

[0066] Step 1: Add 200 g of vinyl-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s and 1.25 g of tetramethyldisiloxane to a 500 mL four-necked flask. Stir and mix under nitrogen protection, heat to 60 °C, slowly add 5 ppm of platinum-divinyltetramethyldisiloxane complex, react for 3 hours, remove low-boiling substances at -0.10 MPa for 1 hour to obtain hydrogen-terminated polysiloxane.

[0067] Step 2: Add 2.78 g F1 to the hydrogen-terminated polysiloxane obtained in Step 1 and continue the reaction for 3 hours to obtain a terminally functionalized polysiloxane with m of approximately 1078. See Table 2 for details.

[0068]

[0069] Example 2: Preparation of terminal-functionalized polysiloxanes

[0070] Except for step 2, in which the same amount of F2 is used instead of F1, the other steps are the same as in Example 1, resulting in a terminal functionalized polysiloxane with m of approximately 1108. Detailed information is shown in Table 2.

[0071]

[0072] Example 3: Preparation of terminal-functionalized polysiloxanes

[0073] Except for step 2, in which the same amount of F3 is used instead of F1, the other steps are the same as in Example 1, resulting in a terminal-functionalized polysiloxane with m of approximately 1099. Detailed information is shown in Table 2.

[0074]

[0075] Example 4: Preparation of terminal-functionalized polysiloxanes

[0076] Except for step 2, in which the same amount of F4 is used instead of F1, the other steps are the same as in Example 1, resulting in a terminal functionalized polysiloxane with m of approximately 1135. Detailed information is shown in Table 2.

[0077]

[0078] Example 5: Preparation of terminal-functionalized polysiloxanes

[0079] Except for step 2, in which the same amount of F5 is used instead of F1, the other steps are the same as in Example 1, resulting in a terminal functionalized polysiloxane with m of approximately 1157. For details, please refer to Table 2.

[0080]

[0081] Example 6: Preparation of terminal-functionalized polysiloxanes

[0082] Except for step 2, in which the same amount of F6 was used instead of F1, the other steps were the same as in Example 1, resulting in a terminal-functionalized polysiloxane with m of approximately 1157. Detailed information is shown in Table 2.

[0083]

[0084] Example 7: Preparation of terminal-functionalized polysiloxanes

[0085] Except for the use of the same amount of F7 in step 2, the other steps are the same as in Example 1, resulting in a terminally functionalized polysiloxane with m approximately 1081. Detailed information is shown in Table 2.

[0086]

[0087] Example 8: Preparation of terminal-functionalized polysiloxanes

[0088] Except for step 2, in which the same amount of F8 is used instead of F1, the other steps are the same as in Example 1, resulting in a terminal functionalized polysiloxane with m of approximately 1032. Detailed information is shown in Table 2.

[0089]

[0090] Example 9: Preparation of terminal-functionalized polysiloxanes

[0091] Except for step 2, where the same amount of F8 is used instead of F1, the other steps are the same as in Example 1, resulting in a terminal-functionalized polysiloxane with m approximately 1314. Detailed information is shown in Table 2.

[0092]

[0093] Example 10: Preparation of terminal-functionalized polysiloxanes

[0094] Except for the use of the same mass of terminal vinylphenyl silicone oil in step 1, the other steps are the same as in Example 1, resulting in terminal functionalized polysiloxanes with m approximately 287 and q approximately 287. Detailed information is shown in Table 2.

[0095]

[0096] Comparative Example 1: Preparation of Common Alkoxy-Terminated Polysiloxanes

[0097] Except for the amount of the same substance used in step 2 Except for F1, the other steps are the same as in Example 1 to obtain a common alkoxy-terminated polysiloxane with m of approximately 947. For details, please refer to Table 2.

[0098]

[0099] Comparative Example 2: Preparation of Common Alkoxy-Terminated Polysiloxanes

[0100] Except for the amount of the same substance used in step 2 Except for F1, the other steps are the same as in Example 1, to obtain a common alkoxy-terminated polysiloxane with m of approximately 1135. Detailed information is shown in Table 2.

[0101]

[0102] Comparative Example 3: Preparation of Common Alkoxy-Terminated Polysiloxanes

[0103] Except for the amount of the same substance used in step 2 Except for replacing F1 and 1 ppm of Pt catalyst, the other steps are the same as in Example 1 to obtain a common alkoxy-terminated polysiloxane with m of approximately 1073. Detailed information is shown in Table 2.

[0104]

[0105] Comparative Example 4: Preparation of Common Alkoxy-Terminated Polysiloxanes

[0106] Except for the use of the same mass of terminal vinylmethyl silicone oil in step 1, the other steps are the same as in Example 1, yielding a common alkoxy-terminated polysiloxane with m approximately 690. Detailed information is shown in Table 2.

[0107]

[0108] Comparative Example 5: Preparation of Common Alkoxy-Terminated Polysiloxanes

[0109] Except for the use of the same mass of terminal vinylmethyl silicone oil and 30 ppm of Pt catalyst in step 1, the other steps are the same as in Example 1, to obtain a common alkoxy-terminated polysiloxane, m is 1, and details are shown in Table 2.

[0110]

[0111] Table 2. Formulations and Basic Performance of Examples and Comparative Examples

[0112]

[0113] a: Terminal vinyl methyl silicone oil (20000 mPa·s); b: Terminal vinyl methyl phenyl silicone oil (30000 mPa·s); c: Terminal vinyl methyl silicone oil (5000 mPa·s); d: Terminal vinyl tetramethylsiloxane; e: Molar ratio of vinyl to silane-hydrogen bond is 1:1.3; f: Molar ratio of vinyl to silane-hydrogen bond is 1:1.05

[0114] Preparation of dealcoholized silicone rubber

[0115] The dealcohol-type silicone rubber comprises the following components: 700 g of the end-functionalized polysiloxane rubber prepared in the examples or the ordinary alkoxy-terminated polysiloxane prepared in the comparative examples, 100 g of dimethyl silicone oil, 150 g of hydrophobic fumed silica, 12 g of methyltrimethoxysilane, 5 g of 3-aminopropyltriethoxysilane (KH550), and 2 g of dibutyltin dinecidate.

[0116] Preparation steps:

[0117] Step A: Mix the terminal-functionalized polysiloxane adhesive prepared in the example or the ordinary alkoxy-terminated polysiloxane prepared in the comparative example with dimethyl silicone oil at 40°C for 10 minutes to obtain the first mixture;

[0118] Step B: Disperse the first mixture with hydrophobic fumed silica at high speed for 20 minutes, then disperse under vacuum for 60 minutes to obtain the second mixture;

[0119] Step C: Mix the second mixture with methyltrimethoxysilane and KH550 under vacuum for 30 minutes to obtain the third mixture;

[0120] Step D: Mix the third mixture with dibutyltin dineodecanate for 15 minutes to obtain a dealcoholized silicone rubber.

[0121] Table 3 Test data for de-alcoholized silicone rubber

[0122]

[0123] a: The functionalized polysiloxane used in Comparative Example 6 was a hydroxyl-terminated polysiloxane (107) with a viscosity of 20000 mPa·s.

[0124] Performance testing methods and results analysis

[0125] 1. Storage stability test: The silicone rubber samples prepared in each example and comparative example were sealed and stored under aging conditions at 80°C. Their surface drying time and viscosity changes were tested periodically, and the results are shown in Table 3. As can be seen from Table 3, compared with other samples using alkoxy-terminated end-capping, Comparative Example 6 (non-alkoxy-terminated polysiloxane) showed a larger change in surface drying time and viscosity after being stored at 80°C for two weeks, thus indicating that alkoxy-termination is crucial for improving the storage stability of silicone rubber.

[0126] 2. Adhesion Performance Test: The adhesion strength of the silicone rubbers prepared in each example and comparative example to aluminum plates, glass, and PC boards was tested according to GB / T 13477.17-2002 standard. The results are shown in Table 3. Table 3 shows that the adhesion strength of the samples in Examples 1-9 to various substrates is significantly higher than that of Comparative Examples 1-6. Specifically, Comparative Example 1 lacks active groups (silanol groups or alkoxysilane groups), resulting in inability to crosslink and achieve effective adhesion. Comparative Example 2, lacking additional epoxy groups, exhibits lower adhesion than the examples. Comparative Example 3, lacking both epoxy and amino groups, further reduces adhesion. Furthermore, compared to Example 1, Comparative Examples 4 and 5 suffer from adhesion failure due to the excessively small molecular weight of the functionalized silicone rubber, leading to cohesive failure. Example 10, possessing rigid phenyl groups and a certain degree of polarity, exhibits superior silicone rubber adhesion compared to other examples.

[0127] 3. Mechanical Property Testing: The tensile strength and elongation at break of the silicone rubbers prepared in each example and comparative example were tested according to GB / T 528-2009 standard. The results are shown in Table 3. Table 3 shows that the tensile strength of samples from Examples 1-10 was 1.0-1.6 MPa, and the elongation at break was 199-229%, which was superior to that of Comparative Examples 1-6. Specifically, compared to Example 1, Comparative Example 1 lacked active groups (silanol groups or alkoxysilane groups), resulting in the inability to crosslink and form an elastic crosslinked body. Furthermore, compared to Example 1, Comparative Examples 4 and 5 had lower strength after crosslinking because the molecular weight of the functionalized silicone rubber was too small.

[0128] 4. Viscosity Peak Test: The base adhesives of each example and comparative example were mixed with 2% tetraisopropyl titanate, and the occurrence of viscosity peaks was observed. The results are shown in Table 3. Table 3 shows that the base adhesives of Examples 1-10 and Comparative Examples 1-5 did not exhibit viscosity peaks; however, the viscosity of the 107 adhesive in Comparative Example 6 increased sharply within 10 seconds after the addition of tetraisopropyl titanate, showing a significant viscosity peak. This indicates that alkoxy protection of hydroxyl-terminated polysiloxanes can avoid viscosity peak problems during production.

[0129] 5. Filler Dispersion Test: During the test, the prepared dealcoholized silicone rubber was scraped from the deep end of the groove (larger scale value) to the shallow end (smaller scale value). When the size of the solid particles in the material is larger than the groove depth at its location, the particles will be "revealed" on the scraped surface. By observing the position where these particles first appear in rows or clusters, the corresponding depth can be read, which is the fineness value. The results are shown in Table 3. As can be seen from Table 3, compared with Examples 1-10, Comparative Examples 1-3 and Comparative Example 6 have larger fineness values ​​and poorer dispersion because the terminal functionalized groups do not all have alkoxy groups, nitrogen-containing groups, epoxy groups, or other heterocyclic groups.

[0130] In summary, this invention introduces polyalkoxysilanes containing heteroatom groups (such as N, O, etc.) at the ends of polysiloxanes via hydrosilylation reactions. The resulting alkoxy-terminated polysiloxanes exhibit excellent storage stability, adhesive properties, and filler compatibility. The dealcoholized silicone rubber prepared using this polymer as the base material avoids the "viscosity peak" phenomenon during production and possesses excellent storage stability, adhesive properties, and comprehensive mechanical properties, making it particularly suitable for bonding and sealing applications in demanding fields such as electronics, construction, and automotive.

[0131] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A terminal-functionalized polysiloxane, characterized in that, The structural formula is as follows: ， Among them, R 1 R 2 R 3 R is an alkyl, alkoxy, or halogen atom containing 1 to 12 carbon atoms. 1 R 2 R 3 Same or different; R 4 and R 5 R is alkyl, aryl, vinyl, H or a combination thereof. 4 R 5 Same or different; It is a group containing an epoxy, ether, alkane, amino, oxygen-containing heterocycle, nitrogen-containing heterocycle or H atom or a combination thereof; p is 0-10, n is 1-100, m is 1-1200, and q is 0-300.

2. The terminal-functionalized polysiloxane according to claim 1, characterized in that, The polysiloxane has a weight-average molecular weight of 100 to 1,000,000 g / mol.

3. The method for preparing the end-functionalized polysiloxane according to claim 1 or 2, characterized in that, Includes the following steps: 1) Mix vinyl-terminated polysiloxane and hydrogen-containing silane in a ratio of vinyl to silane-hydrogen bond of 1:(1.05-1.3), add platinum catalyst, and react at 60-110℃ for 1-4 hours to obtain hydrogen-terminated polysiloxane. 2) The hydrogen-terminated polysiloxane and the vinyl-functionalized polysiloxane are mixed in a ratio of 1:(1.05-1.3) of silane-hydrogen bond to vinyl group, and a platinum catalyst is added. The mixture is reacted at 70-110°C for 1-3 hours to obtain the terminal-functionalized polysiloxane.

4. The method for preparing end-functionalized polysiloxane according to claim 3, characterized in that, The structural formula of the terminal vinyl polysiloxane is as follows: ； R 4 and R 5 R is alkyl, aryl, vinyl, H or a combination thereof. 4 R 5 Same or different; m is 1-1200, q is 0-300; The hydrogen-containing silane is one or more of 1,1,3,3-tetramethyldisiloxane and hydrogen-terminated polydimethylsiloxane, with the following general structural formula: n is 1-100.

5. The method for preparing end-functionalized polysiloxane according to claim 3, characterized in that, The structure of the vinyl-containing functionalized siloxane is as follows: ； R 1 R 2 R 3 R is an alkyl, alkoxy, or halogen atom containing 1 to 12 carbon atoms. 1 R 2 R 3 Same or different; It is a group containing an epoxy, ether, alkane, amino, oxygen-containing heterocycle, nitrogen-containing heterocycle, H atom, or a combination thereof; p is 0-10.

6. The method for preparing end-functionalized polysiloxane according to claim 5, characterized in that, The method for synthesizing the vinyl-containing functionalized siloxane includes the following steps: Step 1: Add alkali to a mixture of silane coupling agent containing primary amine, toluene, and haloolefin, stir and mix under nitrogen protection, react at 40-80℃ for 4-6 h, cool and let stand, filter and evaporate the solvent to obtain the intermediate. Step 2: Add toluene, heteroatom-containing haloalkanes and base to the intermediate, and react at 40-80℃ for 4-6 h to obtain vinyl-containing functionalized alkoxysilanes.

7. The method for preparing end-functionalized polysiloxane according to claim 6, characterized in that, The silane coupling agent containing a primary amine is any one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, and 3-aminopropyltris(methoxyethoxyethoxy)silane; The haloolefin is any one or more selected from 3-chloro-1-propene, 4-chloro-1-butene, 6-chloro-1-hexene, 7-chloro-1-heptene, 8-chloro-1-octene, 3-bromo-1-propene, 4-bromo-1-butene, 6-bromo-1-hexene, 7-bromo-1-heptene, 8-bromo-1-octene, 3-iodopropene, 4-iodo-1-butene, and 6-iodo-1-hexene; The heteroatom-containing haloalkanes are any one or more of the following: 3-chloro-1,2-epoxypropane, 4-chloro-1,2-epoxybutane, 2-(3-chloropropyl)epoxyethylene, 6-chloro-1,2-epoxyhexane, 3-bromo-1,2-epoxypropane, 4-bromo-1,2-epoxybutane, 2-(3-bromopropyl)epoxyethylene, 6-bromo-1,2-epoxyhexane, 3-iodine-1,2-epoxypropane, 4-iodine-1,2-epoxybutane, 6-iodine-1,2-epoxyhexane, 2-(2-ethoxyethoxy)ethylbromide, 2-(bromomethyl)-1,4-dioxane, 3-bromo-N,N-dimethylpropyl-1-amine, and 4-(3-bromopropyl)morpholine.

8. The method for preparing end-functionalized polysiloxane according to claim 5, characterized in that, The vinyl-containing functionalized alkoxysilane has any of the following F1 to F9 structures: 。 9. The method for preparing end-functionalized polysiloxane according to claim 3, characterized in that, In steps 1) and 2), the amount of chloroplatinic acid, platinum-vinylsiloxane complex, platinum-divinyltetramethyldisiloxane complex, or platinum-vinyl cyclic complex used in each step is 1-100 ppm of the total mass of the reactants.

10. The application of the end-functionalized polysiloxane according to claim 1 or 2, characterized in that, It is used as a base material in de-alcoholized sealants.

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