High-flame-retardant bi-component epoxy modified silyl-terminated polyether sealant and preparation method thereof

Abstract

The invention relates to the technical field of sealants, in particular to a high-flame-retardant bi-component epoxy modified silyl-terminated polyether sealant and a preparation method thereof. The coating is composed of a component A and a component B, the component A comprises the following raw material components in parts by mass: 60-100 parts of a silane-terminated polyether polymer, 10-30 parts of a core-shell structure flame retardant, 12-38 parts of an auxiliary flame retardant, 1-5 parts of a stabilizer, 2-8 parts of a thixotropic agent, 3-8 parts of a curing agent and 2-8 parts of a silane coupling agent; the component B is prepared from the following raw material components in parts by mass: 20 to 50 parts of epoxy resin, 20 to 60 parts of auxiliary flame retardant, 1 to 5 parts of ionic liquid, 0.5 to 2 parts of catalyst and 0.5 to 1.5 parts of water; the core-shell structure flame retardant is aluminum hydroxide coated titanium dioxide; aiming at the defect of insufficient flame retardant property of the existing modified silane-terminated polyether sealant, high flame retardant property and excellent mechanical property are realized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of sealant, in particular to high-flame-retardant two-component epoxy-modified end-silane-based polyether sealant and a preparation method thereof. BACKGROUND

[0002] End-silane-based polyether (also known as MS polymer) sealant has been widely used in the fields of construction, automobiles and new energy power batteries, and has become a key material in power battery package structure sealing and cell protection, because it has the weather resistance of silicone sealant, the flexibility of polyurethane sealant, and is low in pollution and easy to construct. In order to further improve the body strength and substrate adhesion of MS glue, the industry often uses resin for hybrid modification. The high strength characteristics of the resin are used to form a two-component modified MS sealant, which not only retains the anti-deformation ability of MS polymer, but also improves the adhesion reliability through the resin, and solves the problem of slow curing of single-component glue, which is suitable for industrial high-efficiency assembly requirements.

[0003] Since the main chain of MS polymer is mainly composed of flammable polyether soft segments, and the resin molecules contain aliphatic methylene chains, both of which are high-hydrocarbon organic matter, they are easy to burn continuously in a high-temperature environment. In the combustion process, the silica ash structure formed by the decomposition of the end-siloxane group of MS polymer is loose and easy to fall off, which is difficult to build an effective heat and oxygen barrier. The silica ash cannot effectively prevent the thermal decomposition of the internal polymer and the escape of flammable gas, and the flame-retardant effect is very weak, which restricts the safety of the application scene. At the same time, in order to meet the operation requirements of manual or equipment glue application, the mechanical properties of the existing sealant are difficult to adapt to the requirements of the scene such as power battery, and the glue body is easy to crack under long-term vibration working conditions. Moreover, traditional flame-retardant modification relies on a single inorganic flame retardant, which has poor compatibility with MS polymer and resin matrix, and is easy to agglomerate, which also leads to a decrease in the toughness of the sealant, making it difficult to achieve a balance between flame retardancy, mechanical properties and workability, and affecting its application expansion in high-end fields. SUMMARY

[0004] In view of the insufficient flame-retardant performance of the existing modified end-silane-based polyether sealant, the application provides a high-flame-retardant two-component epoxy-modified end-silane-based polyether sealant and a preparation method thereof.

[0005] In a first aspect, the application provides a high-flame-retardant two-component epoxy-modified end-silane-based polyether sealant, which adopts the following technical scheme: the high-flame-retardant two-component epoxy-modified end-silane-based polyether sealant is composed of component A and component B; the component A includes the following raw material components in parts by mass: 60-100 parts of end-silane-based polyether polymer, 10-30 parts of core-shell structure flame retardant, 12-38 parts of auxiliary flame retardant, 1-5 parts of stabilizer, 2-8 parts of thixotropic agent, 3-8 parts of curing agent, and 2-8 parts of silane coupling agent; the component B includes the following raw material components in parts by mass: 20-50 parts of epoxy resin, 20-60 parts of auxiliary flame retardant, 1-5 parts of ionic liquid, 0.5-2 parts of catalyst, and 0.5-1.5 parts of water; the core-shell structure flame retardant is aluminum hydroxide-coated titanium dioxide; and the auxiliary flame retardant is one or more of calcium carbonate, montmorillonite, magnesium hydroxide, and zinc oxide.

[0006] The general formula of the end-silane-based polyether polymer is as follows: n is an integer in 200-500, R1 is -CH3, and R2 is -CH3, -CH2CH3, -OCH3, or -OCH2CH3. Preferably, the epoxy resin is selected from one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, and o-cresylic type epoxy resin.

[0007] The application selects an end-silane-based polyether, and the specific end group structure can improve the compatibility with inorganic flame retardants and epoxy resins, and provide structural support for stable dispersion of the flame-retardant component. The core-shell structure flame retardant selects aluminum hydroxide-coated titanium dioxide. On the one hand, the hydrophobic titanium dioxide core can improve the problem of easy agglomeration of aluminum hydroxide, so that it is uniformly distributed in the hybrid matrix. On the other hand, the aluminum hydroxide shell layer can first decompose and absorb heat, has the effect of quickly reducing the temperature of the system and diluting combustible gas, while the core titanium dioxide forms a high-temperature-resistant skeleton, supports the decomposition product aluminum oxide to build a continuous and dense heat and oxygen barrier, avoids loose falling of the flame-retardant component, and at the same time guarantees the structural integrity of the hybrid matrix. The surface hydroxyl group of aluminum hydroxide can participate in the curing of the end-silane-based polyether, so as to realize stable anchoring and dispersion of the core-shell structure flame retardant in the sealant, and effectively improve the flame-retardant effect. The auxiliary flame retardant is an inorganic filler such as calcium carbonate and montmorillonite, which forms a continuous flame-retardant structure with the core-shell structure flame retardant through physical barrier, catalytic carbonization characteristics, and strengthens the barrier and carbonization effects. The sealant of the application improves the flame-retardant performance from the aspects of heat absorption, temperature reduction, dense barrier, and barrier, and at the same time relies on the hybridization of the end-silane-based polyether and the epoxy resin and the interaction between the material components to balance the mechanical properties and workability of the sealant as a whole.

[0008] Preferably, the preparation method of the titanium dioxide coated with aluminum hydroxide comprises: mixing titanium dioxide with ethanol, then adding silane coupling agent dropwise and stirring for 30-45 min, slowly dropping aluminum isopropyl alcohol solution in ethanol, then slowly dropping nitric acid solution in ethanol at 70-80℃, continuing to stir for 2-4 h, adding ammonia water, adjusting pH to 8-9, continuing to stir for 3-4 h, cooling to room temperature, centrifuging, washing, and drying to obtain titanium dioxide coated with aluminum hydroxide.

[0009] Preferably, the mass ratio of titanium dioxide to aluminum isopropyl alcohol is 1: (0.9-1.2).

[0010] The silane coupling agent is bonded to the surface hydroxyl group of titanium dioxide through hydrolysis, and then the hydrolysis of aluminum isopropyl alcohol promotes the crystallization of aluminum hydroxide, and finally a shell layer is formed on the surface of titanium dioxide to construct the stable core-shell structure of the application. Therefore, if the content of aluminum isopropyl alcohol is too high, the shell layer is easy to agglomerate, which reduces the dispersibility of the core-shell structure flame retardant in the matrix, reduces the flame retardant efficiency, reduces the toughness, and is easy to appear the phenomenon of colloid cracking; if the content of aluminum isopropyl alcohol is too low, the heat absorption and barrier effect is reduced, which affects the sealing and flame retardant performance of the sealant.

[0011] Preferably, the auxiliary flame retardant is montmorillonite and magnesium hydroxide with a mass ratio of 1: (1.2-2).

[0012] More preferably, the montmorillonite is modified montmorillonite, and the preparation method thereof comprises: taking montmorillonite and adding it into water, stirring and dispersing in a 50-60℃ water bath; then adding an ethanol solution containing hyperbranched polyamide dropwise, heating to 75-80℃ and stirring for 4-5 h, centrifuging, washing, and drying to obtain modified montmorillonite.

[0013] More preferably, the magnesium hydroxide is modified magnesium hydroxide, and the preparation method thereof comprises: taking magnesium hydroxide and adding it into a mixture of ethanol and water, stirring in a 50-60℃ water bath, then slowly dropping a mixture containing 2-aminoethyl phosphonic acid, heating to 75-80℃, stirring for 4-5 h, centrifuging, washing, and drying to obtain modified magnesium hydroxide.

[0014] Preferably, the ionic liquid is 1-ethyl-3-methylimidazolium dihydrogen phosphate.

[0015] Preferably, the thixotropic agent is one or both of kaolin and polyamide wax.

[0016] Preferably, the stabilizer is one of vinyltrimethoxysilane and p-toluenesulfonyl isocyanate.

[0017] The modified montmorillonite is introduced with hyperbranched three-dimensional structure, and the terminal amino and amide groups on the surface thereof can interact with the terminal silane-based polyether to form a stable layered barrier structure to prevent the lateral diffusion of flammable gas; and the modified magnesium hydroxide is introduced with amino and phosphonic acid groups to enable the magnesium hydroxide to be effectively embedded in the interlayer and extend outward to form a longitudinal barrier, thereby enhancing the interface bonding with the modified montmorillonite, introducing phosphorus element to strengthen the carbonization performance, and improving the density of the carbon layer at high temperature to avoid loose carbon layer, and the three-dimensional network formed by the interweaving of the two can reduce the amount of flammable gas escaping and reduce the heat transfer efficiency; the barrier continuity and structural stability are improved, and the bonding of the terminal silane-based polyether to the core-shell structure flame retardant and the specific modified auxiliary flame retardant further optimizes the synergy of the two.

[0018] The layered barrier structure of the auxiliary flame retardant and the dense barrier of the core-shell structure can form a stepped heat absorption system. In the initial stage of combustion, the aluminum hydroxide shell layer of the core-shell structure flame retardant decomposes preferentially, quickly absorbs heat, and instantaneously dilutes oxygen and flammable gas generated by the decomposition of the terminal silane-based polyether; then the hyperbranched modified layer of the modified montmorillonite begins to decompose and release nitrogen-containing gas, further diluting the concentration of flammable gas; in the later stage of combustion, the three-dimensional barrier structure of the auxiliary flame retardant carbonizes at high temperature, and based on the fixed-point anchoring of the auxiliary flame retardant and the core-shell structure flame retardant at the terminal silane-based polyether chain end, a titanium dioxide and aluminum oxide protective layer can be formed on the carbon layer, further densifying the carbon layer, significantly improving the stability of the carbon layer during combustion, and thereby strengthening the carbon layer structure and blocking the transfer of oxygen, flammable gas and heat. Strengthening the high-temperature carbon layer skeleton to resist flame scouring, preventing the carbon layer from being oxidized at high temperature, thereby reducing the flame retardant performance, and the interlayer of the montmorillonite can capture toxic gases to reduce smoke density.

[0019] The auxiliary flame retardant enhances the carbon layer density to further block the transfer of heat and gas and block the escape of flammable gas. The ionic liquid 1-ethyl-3-methylimidazolium dihydrogen phosphate can be combined with the interlayer site of the montmorillonite through hydrogen bonding and other interactions to achieve intercalation and dispersion, improving the dispersibility of the montmorillonite; at high temperature, the dihydrogen phosphate radical can quickly capture active free radicals such as OH and H generated in the combustion chain reaction to form stable molecules, interrupting the combustion reaction transfer, and the decomposition of the dihydrogen phosphate radical can promote the formation of the carbon layer, densify the carbon layer, reduce the transfer of heat and flammable gas, and enhance the flame retardant effect, thereby playing an auxiliary flame-retardant role; the thixotropic agent kaolin and polyamide wax form a three-dimensional network to improve the stress of the sealant, ensure vertical surface no-flowing construction, and balance the construction performance and mechanical properties.

[0020] Preferably, the curing agent is one or both of a fatty amine curing agent and 2,4,6-tris(dimethylaminomethyl)phenol.

[0021] Preferably, the fatty amine curing agent is one or more of 2-hydroxybenzylamine, N-benzyl-1,3-propanediamine, diethylenetriamine, and isophorone diamine.

[0022] More preferably, the mass ratio of the fatty amine curing agent to 2,4,6-tris(dimethylaminomethyl)phenol is (1-1.5):1.

[0023] The present application introduces the curing of the epoxy resin system, strengthens the crosslinking density of the sealant, further stabilizes the flame-retardant components in the flame-retardant sealant, and maintains the flame-retardant structure. The inventors have found that the interaction of 2,4,6-tris(dimethylaminomethyl)phenol and N-benzyl-1,3-propanediamine can improve the curing efficiency of the sealant and enhance the curing structure. N-benzyl-1,3-propanediamine is cured to form a crosslinked network. In addition, 2,4,6-tris(dimethylaminomethyl)phenol can reduce the ring-opening energy barrier of the epoxy group, accelerate the curing reaction, and shorten the curing time. Avoiding the brittleness of the sealant caused by excessive crosslinking or insufficient strength caused by insufficient crosslinking, the curing rate and mechanical properties are balanced, and the crosslinked network formed by the curing reaction provides a stable dispersion environment for the flame-retardant filler, ensuring the interaction effect of the flame-retardant system.

[0024] In a second aspect, the present application provides a preparation method of a high-flame-retardant two-component epoxy-modified terminal silane-based polyether sealant, which adopts the following technical scheme: The preparation method of the high-flame-retardant two-component epoxy-modified terminal silane-based polyether sealant comprises the following steps: S1: a preparation method of component A comprises mixing a terminal silane-based polyether polymer, a core-shell structure flame retardant, and an auxiliary flame retardant at a temperature of 100-120°C and a pressure of 0.05-0.09 MPa for 4-6 h; the temperature is reduced to 30-40°C, and a stabilizer, a thixotropic agent, a curing agent, and a silane coupling agent are added and mixed under an inert atmosphere, and vacuum degassing is performed to obtain component A; S2: a preparation method of component B comprises vacuum mixing an epoxy resin, an auxiliary flame retardant, an ionic liquid, a catalyst, and water to obtain component B; S3: uniformly mixing components A and B at a volume ratio of 1-2:1 to obtain the high-flame-retardant two-component epoxy-modified terminal silane-based polyether sealant.

[0025] In summary, the present application has the following beneficial effects: 1. The terminal silane-based polyether polymer of the present application retains flexibility and weather resistance due to the polyether soft segment, and the terminal silane group can be hydrolyzed and crosslinked to form an elastic network, forming a hybrid system with the epoxy resin. This not only solves the problem of slow curing of single-component glue, but also disperses the flame retardant through the molecular structure of the polymer, avoiding agglomeration and causing flame retardant failure. The polyether soft segment improves the elongation at break of the sealant, alleviates the cracking of the glue caused by insufficient mechanical properties, and cooperates with the flame-retardant system to balance the flame retardancy and flexibility. Through the selection of the curing components, the tensile strength is further optimized, and finally the sealant has excellent flame retardancy and mechanical properties.

[0026] 2、In the surface of titanium dioxide shell layer, build stable core-shell structure, isopropyl alcohol aluminum content is too high, shell layer is easy to agglomerate, and then reduce the dispersion of core-shell structure flame retardant in the matrix, reduce the flame retardant efficiency, reduce the toughness, easy to appear the phenomenon of gel cracking; Isopropyl alcohol aluminum content is too low, the heat absorption flame retardant and barrier effect is reduced, affect the sealing of the sealant sealing flame retardant performance. DETAILED DESCRIPTION

[0027] The application will be further described in detail below in combination with examples.

[0028] Raw materials Some raw materials used in the preparation examples and examples: epoxy resin E-51 WSR618; hyperbranched polyamide HyPer HPN202; titanium dioxide (anatase) was purchased from Aladdin, kaolin was purchased from Shijiazhuang Leitai Technology Co., Ltd., catalyst was 1,3-dilauryloxy-1,1,3,3-tetrabutyldistannoxane; montmorillonite was Nanocor organic montmorillonite, model number: I.31PS; magnesium hydroxide was purchased from Anhui Zhonghang Technology Development Co., Ltd.; silane-terminated polyether polymer model number: S303H; silane coupling agent was KH-550.

[0029] The related raw materials used in the examples and comparative examples are not marked, which are conventional products that can be purchased in the market.

[0030] Preparation example 1 Preparation of aluminum hydroxide coated titanium dioxide: take 10g titanium dioxide into 200ml ethanol, stirring speed 800rpm for 10min, then add 0.2g KH-550 and stir for 30min, slowly drop 11.2g aluminum isopropyl alcohol in 60ml ethanol solution, at temperature 70℃, slowly drop 2.9mL deionized water and 1mL 1mol / L nitric acid in 20mL ethanol solution, continue to stir for 2h, add 25% dilute ammonia water, adjust pH to 9, continue to stir for 4h, cool to room temperature, centrifuge at 8000rpm for 15min, ethanol washing for 3 times, dry in 120℃ oven for 12h, get aluminum hydroxide coated titanium dioxide.

[0031] Preparation example 2 Preparation of aluminum hydroxide-coated titanium dioxide: 12g of titanium dioxide was added to 200ml of ethanol and stirred at 800rpm for 10min. Then, 0.2g of KH-550 was added dropwise and stirred for 30min. 60ml of ethanol solution containing 9.2g of aluminum isopropoxide was slowly added dropwise. At 70℃, 20ml of ethanol solution containing 2.9mL of deionized water and 1mL of 1mol / L nitric acid was slowly added dropwise. Stirring was continued for 2h. 25% dilute ammonia was added dropwise to adjust the pH to 9. After stirring for 4h, the solution was cooled to room temperature, centrifuged at 8000rpm for 15min, washed 3 times with ethanol, and dried in a 120℃ oven for 12h to obtain aluminum hydroxide-coated titanium dioxide.

[0032] Preparation Example 3 Preparation of aluminum hydroxide-coated titanium dioxide: 9g of titanium dioxide was added to 200ml of ethanol and stirred at 800rpm for 10min. Then, 0.2g of KH-550 was added dropwise and stirred for 30min. 60ml of ethanol solution containing 12.2g of aluminum isopropoxide was slowly added dropwise. At 70℃, 20ml of ethanol solution containing 2.9mL of deionized water and 1mL of 1mol / L nitric acid was slowly added dropwise. Stirring was continued for 2h. 25% dilute ammonia was added dropwise to adjust the pH to 9. After stirring for 4h, the solution was cooled to room temperature, centrifuged at 8000rpm for 15min, washed three times with ethanol, and dried in a 120℃ oven for 12h to obtain aluminum hydroxide-coated titanium dioxide.

[0033] Preparation Example 4 Modified montmorillonite: Add 10g of montmorillonite to 200ml of water and stir to disperse in a 60℃ water bath; then add dropwise 100ml of ethanol solution containing 5g of hyperbranched polyamide, heat to 75℃ and stir for 4h, centrifuge at 8000rpm for 15min, wash 3 times with ethanol, and dry in an 80℃ oven for 12h to obtain modified montmorillonite.

[0034] Preparation Example 5 Modified magnesium hydroxide: Take 10g of magnesium hydroxide and add it to 200mL of a mixture of ethanol and water (volume ratio 3:1). Sonicate for 40min, stir in a 60℃ water bath, and then slowly add 50mL of a mixture containing 3g of 2-aminoethylphosphonic acid (ethanol:water = 3:1). Heat to 80℃, stir and react for 5h, centrifuge at 8000rpm for 15min, wash 3 times with ethanol, vacuum dry at 70℃ for 10h, and grind to obtain organic modified magnesium hydroxide. Example

[0035] The high flame-retardant two-component epoxy modified end-silane-based polyether sealant is composed of component A and component B; component A: 75 g of end-silane-based polyether polymer, 20 g of core-shell structure flame retardant, 30 g of auxiliary flame retardant, 3 g of stabilizer, 4 g of thixotropic agent, 5 g of curing agent, and 2 g of silane coupling agent; component B: 35 g of epoxy resin, 20 g of auxiliary flame retardant, 3 g of ionic liquid, 1.5 g of catalyst, and 1.5 g of water; the core-shell structure flame retardant is the titanium dioxide coated with aluminum hydroxide prepared in Preparation Example 1; the auxiliary flame retardant is the modified montmorillonite prepared in Preparation Example 4 and the modified magnesium hydroxide prepared in Preparation Example 5 with a mass ratio of 1:1.5; the stabilizer is vinyl trimethoxysilane; the thixotropic agent is kaolin and polyamide wax with a mass ratio of 1:1; the curing agent is 2-hydroxybenzylamine and 2,4,6-tris(dimethylaminomethyl)phenol with a mass ratio of 1.5:1; the ionic liquid is 1-ethyl-3-methylimidazolium dihydrogen phosphate; and the catalyst is 1,3-dilauroyl-oxy-1,1,3,3-tetrabutyldistannoxane.

[0036] The preparation method comprises the following steps: the preparation method of component A comprises the following steps: mixing the end-silane-based polyether polymer, the core-shell structure flame retardant, and the auxiliary flame retardant at a temperature of 120 DEG C and under a pressure of 0.09 MPa for 4 h; reducing the temperature to 40 DEG C, and then adding the stabilizer, the thixotropic agent, the curing agent, and the silane coupling agent; mixing under a nitrogen atmosphere, and vacuum defoaming to obtain component A; the preparation method of component B comprises the following steps: vacuum mixing the epoxy resin, the auxiliary flame retardant, the ionic liquid, the catalyst, and water to obtain component B; uniformly mixing component A and component B at a volume ratio of 1:1 to obtain the high flame-retardant two-component epoxy modified end-silane-based polyether sealant. Example

[0037] The difference between this example and Example 1 is that the core-shell structure flame retardant is the titanium dioxide coated with aluminum hydroxide prepared in Preparation Example 2. Example

[0038] The difference between this example and Example 1 is that the core-shell structure flame retardant is the titanium dioxide coated with aluminum hydroxide prepared in Preparation Example 3. Example

[0039] The difference between this example and Example 1 is that the auxiliary flame retardant is the modified montmorillonite prepared in Preparation Example 4. Example

[0040] The difference between this example and Example 1 is that the auxiliary flame retardant is the modified magnesium hydroxide prepared in Preparation Example 5. Example

[0041] The difference between this example and Example 1 is that the auxiliary flame retardant is the montmorillonite and the modified magnesium hydroxide prepared in Preparation Example 5 with a mass ratio of 1:1.5. Example

[0042] The difference between this example and Example 1 is that the auxiliary flame retardant is the montmorillonite prepared in Preparation Example 4 and magnesium hydroxide in a mass ratio of 1:1.5. Example

[0043] The difference between this example and Example 1 is that the ionic liquid is tetrabutylammonium hydrogen phosphate. Example

[0044] The difference between this example and Example 1 is that the curing agent is 2-hydroxybenzylamine. Example

[0045] The difference between this example and Example 1 is that the curing agent is diethylenetriamine and 2,4,6-tris(dimethylaminomethyl)phenol in a mass ratio of 1.5:1.

[0046] Comparative Example 1 The difference between this comparative example and Example 1 is that the core-shell structure flame retardant is replaced with equal mass ratio of aluminum hydroxide and titanium dioxide (mass ratio 1:1).

[0047] Comparative Example 2 The difference between this comparative example and Example 1 is that the core-shell structure flame retardant is not added to the A component.

[0048] The performance test of the high flame-retardant two-component epoxy-modified silyl-terminated polyether sealant prepared in Examples 1-10 and Comparative Examples 1-2 is carried out by the following method: a. The oxygen index and UL94 vertical burning grade test method refers to the GB / T10707 standard; b. The tensile strength test method refers to the GB / T528 standard; The performance results are shown in Table 1: Table 1 Performance test results Limiting oxygen index (%) UL94 flame retardant rating 24h cured tensile strength (MPa) Example 1 36 V0 6.9 Example 2 35 V0 6.8 Example 3 34 V0 6.6 Example 4 31 V1 6.7 Example 5 30 V1 6.6 Example 6 32 V1 6.4 Example 7 29 V1 6.2 Example 8 34 V0 6.7 Example 9 35 V0 6.4 Example 10 34 V1 6.6 Comparative Example 1 27 V2 6.5 Comparative Example 2 24 V2 7.1 As can be seen from Table 1, compared with Examples 1-7 and Comparative Examples 1-2, the application realizes the improvement of flame-retardant performance and mechanical properties by using the core-shell structure flame retardant, the auxiliary flame retardant, and the synergistic curing system. The core-shell structure flame retardant, nano-aluminum hydroxide coated titanium dioxide, has the functions of heat absorption, flame retardation, rigid reinforcement, and barrier stability, interacts with the three-dimensional barrier network formed by the modified nano-montmorillonite and magnesium hydroxide, has gradient flame-retardant performance in the initial, middle, and late stages of combustion, and significantly improves the flame-retardant performance through the mutual promotion of heat absorption, physical barrier, and catalytic carbon formation. The hybrid crosslinking of the silyl-terminated polyether and the epoxy resin, combined with the good compatibility of the flame retardant and the matrix, ensures the balance of the tensile strength and flexibility. The application greatly improves the flame retardancy while maintaining good mechanical properties by adding the core-shell structure flame retardant.

[0049] As can be seen from Comparative Example 1 and Examples 9-10, the interaction of 2,4,6-tris(dimethylaminomethyl)phenol and N-benzyl-1,3-propanediamine can enhance the curing structure, N-benzyl-1,3-propanediamine is cured to form a crosslinked network, a more compact and high-temperature-resistant crosslinked network is formed, the mechanical properties are optimized, and meanwhile the crosslinked network formed by the curing reaction provides a stable dispersion environment for the flame-retardant filler, thereby ensuring the interaction effect of the flame-retardant system.

[0050] The above are preferred embodiments of the present application, but do not limit the protection scope of the present application, and therefore: any equivalent changes made on the basis of the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A high flame-retardant two-component epoxy-modified silane-terminated polyether sealant, characterized in that: It is composed of component A and component B; component A includes the following raw material components in parts by weight: 60-100 parts of silane-terminated polyether polymer, 10-30 parts of core-shell flame retardant, 12-38 parts of auxiliary flame retardant, 1-5 parts of stabilizer, 2-8 parts of thixotropic agent, 3-8 parts of curing agent, and 2-8 parts of silane coupling agent; component B includes the following raw material components in parts by weight: 20-50 parts of epoxy resin, 20-60 parts of auxiliary flame retardant, 1-5 parts of ionic liquid, 0.5-2 parts of catalyst, and 0.5-1.5 parts of water; the core-shell flame retardant is aluminum hydroxide-coated titanium dioxide; the auxiliary flame retardant is selected from one or more of montmorillonite, magnesium hydroxide, molybdenum trioxide, and antimony trioxide.

2. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 1, characterized in that: The general formula of the terminal silane polyether polymer is: n is any integer between 200 and 500, R1 is -CH3, and R2 is -CH3, -CH2CH3, -OCH3, or -OCH2CH3.

3. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 1, characterized in that: The preparation method of aluminum hydroxide-coated titanium dioxide includes: adding titanium dioxide to ethanol and mixing, then adding silane coupling agent and stirring for 30-45 minutes, slowly adding an ethanol solution containing aluminum isopropoxide, and then slowly adding an ethanol solution containing nitric acid at a temperature of 70-80℃, continuing to stir for 2-4 hours, adding ammonia water to adjust the pH to 8-9, continuing to stir for 3-4 hours, cooling to room temperature, centrifuging, washing, and drying to obtain aluminum hydroxide-coated titanium dioxide.

4. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 3, characterized in that: The mass ratio of titanium dioxide to aluminum isopropoxide is 1:(0.9-1.2).

5. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 1, characterized in that: The thixotropic agent is one or both of kaolin and polyamide wax.

6. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 1, characterized in that: The curing agent is one or two of fatty amine curing agents and 2,4,6-tris(dimethylaminomethyl)phenol.

7. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 1, characterized in that: The ionic liquid is 1-ethyl-3-methylimidazolium dihydrogen phosphate.

8. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 1, characterized in that: The auxiliary flame retardants are modified montmorillonite and modified magnesium hydroxide.

9. The high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to claim 1, characterized in that: The modified montmorillonite is prepared by adding montmorillonite to water and stirring to disperse it in a water bath at 50-60℃; then adding an ethanol solution containing hyperbranched polyamide dropwise, heating to 75-80℃ and stirring for 4-5 hours, centrifuging, washing, and drying to obtain modified montmorillonite; the modified magnesium hydroxide is prepared by adding magnesium hydroxide to a mixture of ethanol and water, stirring in a water bath at 50-60℃, then slowly adding a mixture containing 2-aminoethylphosphonic acid dropwise, heating to 75-80℃, stirring and reacting for 4-5 hours, centrifuging, washing, and drying to obtain modified magnesium hydroxide.

10. A method for preparing the high flame-retardant two-component epoxy-modified silane-terminated polyether sealant according to any one of claims 1-9, characterized in that, Includes the following steps: S1: The preparation method of component A includes: mixing terminal silane polyether polymer, core-shell structure flame retardant and auxiliary flame retardant at a temperature of 100-120℃ and 0.05-0.09MPa for 4-6 hours; cooling the temperature to 30-40℃, adding stabilizer, thixotropic agent, curing agent and silane coupling agent, mixing under an inert atmosphere, and vacuum degassing to obtain component A; S2: The preparation method of component B includes: vacuum mixing epoxy resin, auxiliary flame retardant, ionic liquid, catalyst and water to obtain component B; S3: Mix component A and component B uniformly at a volume ratio of 1-2:1 to obtain a high flame retardant two-component epoxy-modified silane-terminated polyether sealant.

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