High-viscosity modified silane sealant and preparation method thereof

Abstract

The invention discloses a high-viscosity modified silane sealant and a preparation method thereof, and belongs to the field of polymer sealing materials. The sealant is prepared from the following raw materials: 10-50 parts of silane-terminated polyether resin; 5 to 15 parts of auxiliary resin; 5 to 20 parts of low-viscosity polyether; 0.5 to 3 parts of a dewatering agent; 0.1 to 1 part of an antioxidant; 0.5 to 5 parts of a silane coupling agent; 1 to 5 parts of gas phase silicon powder; 2 to 10 parts of a plasticizer; 20 to 60 parts of nano calcium carbonate; 0.1 to 1 part of a catalyst; and 0-2 parts of color paste. The sealant has high bonding strength to an aluminum base material and electrophoresis steel, and is especially suitable for sealing scenes with extremely high requirements on metal bonding strength and durability, such as a new energy automobile battery shell, an automobile body, traffic transportation equipment and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer sealing materials, and particularly relates to a high-viscosity modified silane sealant and a preparation method thereof. BACKGROUND

[0002] Modified silane sealant (MS sealant) has been widely used in industrial manufacturing and building fields due to its advantages such as environmental protection, solvent-free, good weather resistance, and wide bonding substrates. The core component is a silane-terminated polyether resin, which catalytically undergoes hydrolysis-condensation reaction through moisture in the air to form a Si-O-Si crosslinking network, thereby realizing curing.

[0003] However, in high-end industrial applications such as new energy automobile battery packs and automobile body welding, the sealant not only needs to have basic sealing function, but also requires high and durable adhesive strength to various aluminum alloys (such as 3003, 6061, 5083) and electrophoresis steel with coating. The MS glue in the prior art often cannot balance the high viscosity to ensure the anti-flowing performance while considering the excellent adhesion to the above-mentioned metals, especially the non-polar or low surface energy coating (such as electrophoresis layer). Commonly used adhesion means, such as adding commercially available silane-modified resin, can improve the viscosity to a certain extent, but the number and distribution of active silane functional groups in the molecular structure are limited, which causes a bottleneck in improving the adhesion performance, resulting in that the sealant is prone to adhesion failure after long-term storage and harsh environment (such as high-low temperature cycle and damp heat aging).

[0004] Therefore, how to develop a new type of auxiliary resin which can significantly improve the viscosity of the system and greatly enhance the interfacial bonding force with the metal substrate through the molecular structure design, and based on this, prepare a high-viscosity modified silane sealant with excellent comprehensive performance, has become a technical problem to be solved in the field.

[0005] Therefore, the application is provided. SUMMARY

[0006] The application aims to provide a high-viscosity modified silane sealant and a preparation method thereof, which can have high adhesive strength to aluminum alloy substrates and electrophoresis steel, has excellent comprehensive performance, and has a simple preparation process, is suitable for industrial production, and thus well solves the problems in the prior art.

[0007] The application is achieved by the following technical scheme. A high-viscosity modified silane sealant comprises the following raw materials in parts by weight: Silane-terminated polyether resin: 10-50 parts; Auxiliary resin: 5-15 parts; Low-viscosity polyether: 5-20 parts; Water removing agent: 0.5-3 parts; Antioxidant: 0.1-1 parts; Silane coupling agent: 0.5-5 parts; Fumed silica: 1-5 parts; Plasticizer: 2-10 parts; Nano calcium carbonate: 20-60 parts; Catalyst: 0.1-1 parts; Color paste: 0.5-2 parts.

[0008] Preferably, in the above-mentioned sealant, the auxiliary resin uses one or more of high-viscosity modified silane resin, terpene phenol resin, polyallyl silane resin, and hydrogenated petroleum resin.

[0009] Preferably, in the above-mentioned sealant, the high-viscosity modified silane resin is a high-viscosity modified silane resin with a plurality of methoxysilane end groups synthesized in the following manner, which has a molecular structure with TMP as the core and three branched chains, and each branched chain has a star structure with one trimethoxysilane group connected by a urea bond at the end, and the synthesis steps include: Step 21, synthesis of intermediate A: ring-opening polymerization of trimethylolpropane as the starting agent with propylene oxide in the presence of a catalyst to generate a trifunctional polyether triol as intermediate A, the reaction formula is as follows: ; Step 12, isocyanate: reaction of intermediate A generated in step 11 with excess diphenylmethane diisocyanate (MDI) to generate a prepolymer with a -NCO end as intermediate B, the reaction formula is as follows: ; Step 13, silanization capping: reaction of the -NCO group at the end of intermediate B generated in step 12 with a secondary amino silane coupling agent to perform silanization capping, i.e., to obtain the auxiliary resin, the reaction formula is as follows: .

[0010] Preferably, in the above-mentioned sealant, the end-silane-based polyether resin is a silane-terminated polyether with a viscosity of 5000-20000 mPa s at 25°C.

[0011] Preferably, in the above-mentioned sealant, the low-viscosity polyether polyol is a polyether polyol with a number average molecular weight of 500-3000 and a viscosity of 50-500 mPa s at 25°C; The water removal agent uses one or more of vinyltrimethoxysilane, methyltrimethoxysilane, and phenyltrimethoxysilane; The antioxidant is one or more of antioxidant 1135, antioxidant 81, and antioxidant 93.

[0012] Preferably, in the above-mentioned sealant, the alkyl coupling agent is one or more of aminosilane coupling agents and epoxysilane coupling agents.

[0013] Preferably, in the above-mentioned sealant, the aminosilane coupling agent is one of γ-aminopropyltriethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; The epoxy silane coupling agent is one of γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane.

[0014] Preferably, in the above-mentioned sealant, the fumed silica powder is hydrophobic fumed silica with a specific surface area of ​​150-200 m² / g; The plasticizer is one or more of diisononyl phthalate, dioctyl phthalate, and diisooctyl adipate. The nano-calcium carbonate used is nano-calcium carbonate with a particle size of 10-100 nm and has undergone stearic acid surface modification treatment. The catalyst is one or more of organotin catalysts and organobismuth catalysts; The color paste is an inorganic pigment color paste.

[0015] A method for preparing the high-viscosity modified silane sealant of the present invention, comprising the following steps, using the raw materials according to the formula of the present invention: Step 1, raw material pretreatment: Place the nano-calcium carbonate in the raw material in an oven at 100-120℃ and dry for 4-6 hours; place the fumed silica powder in an oven at 80-100℃ and dry for 2-3 hours, then set aside. Step 2, base material preparation: Add the terminal silane polyether resin, auxiliary resin, low viscosity polyether and antioxidant from the raw materials to the planetary stirred tank. Control the stirring speed at 20-60 r / min and the dispersion speed at 200-600 r / min. Stir for 10-40 minutes until a uniform base material is formed. Step 3, Powder mixing: Add color paste and pretreated nano-calcium carbonate to the base material obtained in Step 2 in sequence. Control the stirring speed at 20-60 r / min and the dispersion speed at 200-600 r / min. Stir for 20-60 minutes to ensure that the nano-calcium carbonate and color paste filler are evenly dispersed to obtain a mixture. Step 4, addition of auxiliary agents: cool down to 40-50℃, add water scavenger, antioxidant and silane coupling agent to the mixture obtained in step 3, stir while vacuuming to a vacuum degree of -0.08 to -0.1 MPa, stirring speed control at 50-90 r / min, dispersion speed control at 400-900 r / min, stirring for 5-20 minutes; Step 5, catalysis and discharging: continue to cool down to 30-40℃, add catalyst to the reactant of step 4, stir while vacuuming to a vacuum degree of -0.08 to -0.1 MPa, stirring speed control at 20-60 r / min, dispersion speed control at 200-600 r / min, stirring for 5-20 minutes, to obtain high-viscosity modified silane sealant.

[0016] Preferably, in the above method, the fillers in step 3 are added in a step-by-step manner, after adding each filler, stirring for 5-10 minutes, scraping, scraping off the powder wrapped on the planet stirring kettle wall and the paddle, continuing to stir and vacuuming at the same time; after uniform stirring, the next kind of filler is added, so that each kind of filler can be uniformly dispersed in the base material; In steps 3, 4 and 5, the inert gas introduced by releasing vacuum is nitrogen or argon.

[0017] Compared with the prior art, the high-viscosity modified silane sealant and the preparation method thereof provided by the present application have the following beneficial effects: (1) Excellent bonding performance: by introducing the self-synthesized multifunctional auxiliary resin TPMN, the initial tensile shear strength of the sealant to 3003, 6061, 5083 aluminum alloy and electrophoretic steel can exceed 2.0 MPa, which is much better than the comparative product using commercially available auxiliary resin.

[0018] (2) Excellent performance retention rate after aging: due to the more stable and dense crosslinking points provided by the auxiliary resin, the bonding strength retention rate of the sealant after wet heat aging and salt spray test is extremely high, without corrosion and falling off.

[0019] (3) Good workability: through the synergistic effect of the auxiliary resin, fumed silica powder and calcium carbonate, the balance between high viscosity and good extrudability is achieved, and the anti-sagging performance is excellent.

[0020] (4) Stable formula and process: the preparation method has clear process and controllable conditions, and is easy to realize stable production on a large scale.

[0021] The sealant is particularly suitable for new energy automobile battery shell, automobile body, transportation equipment and other sealing scenes with extremely high requirements for metal bonding strength and durability. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific content of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, which do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] First, the following explanations are provided for the terms that may be used in this article: The term "and / or" means that either or both can be achieved simultaneously. For example, X and / or Y means that it includes both "X" or "Y" as well as the three cases of "X and Y".

[0024] The terms "comprising," "including," "containing," "having," or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.) should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0025] The term "composed of" excludes any technical features not expressly listed. When used in a claim, it closes the claim to exclude all technical features other than those expressly listed, except for associated conventional impurities. If the term appears only in a clause of a claim, it limits the claim to the elements expressly listed in that clause; elements recited in other clauses are not excluded from the overall claim.

[0026] The term "parts by mass" indicates the mass ratio between multiple components. For example, if component X is described as x parts by mass and component Y as y parts by mass, then the mass ratio of component X to component Y is x:y. One part by mass can represent any mass; for example, one part by mass can be expressed as 1 kg or 3.1415926 kg, etc. The sum of the parts by mass of all components is not necessarily 100 parts; it can be greater than 100 parts, less than 100 parts, or equal to 100 parts. Unless otherwise stated, parts, proportions, and percentages mentioned herein are all measured by mass.

[0027] When concentration, temperature, pressure, size, or other parameters are expressed as numerical ranges, such ranges should be understood to specifically disclose all ranges formed by any pairing of upper limits, lower limits, or preferred values ​​within that range, regardless of whether the range is explicitly stated; for example, if the numerical range "2 to 8" is stated, then that range should be interpreted to include ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise stated, the numerical ranges described herein include both their endpoints and all integers and fractions within that range.

[0028] The solution provided by this invention will be described in detail below. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they shall be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the embodiments of this invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0029] This invention provides a high-viscosity modified silane sealant, comprising the following raw materials in parts by weight: Silyl-terminated polyether resin: 10-50 parts; Auxiliary resin: 5-15 parts; Low viscosity polyether: 5-20 parts; Dehydrating agent: 0.5–3 parts; Antioxidant: 0.1 to 1 part; Silane coupling agent: 0.5–5 parts; Fumed silica powder: 1-5 parts; Plasticizer: 2-10 parts; Nano-calcium carbonate: 20-60 parts; Catalyst: 0.1–1 part; Color paste: 0.5 to 2 parts.

[0030] In some specific embodiments, the auxiliary resin in the above-mentioned sealant is one or a combination of several of the following: high viscosity modified silane resin, terpene phenolic resin, polyallyl silane resin, and hydrogenated petroleum resin; more preferably, it is a high viscosity modified silane resin. The auxiliary resin can synergistically increase the viscosity of the sealant and the number of active functional groups per unit area, thereby improving the initial tack and appropriately enhancing the interfacial adhesion.

[0031] The high-viscosity modified silane resin is synthesized as follows: a high-viscosity resin with polymethoxysilane end groups. The structure of this resin is similar to that of the known Isocyanurate 88445, and its synthesis steps and structural formula are as follows: The overall synthesis steps are shown in the diagram below: .

[0032] The steps are as follows: Step 11, Synthesis of Intermediate A: Using trimethylolpropane (TMP) as a starting agent, ring-opening polymerization is carried out with propylene oxide (PO) in the presence of a catalyst to generate a trifunctional polyether triol (intermediate A), as shown in the following reaction formula: ; Step 2, isocyanation: Intermediate A is reacted with excess diphenylmethane diisocyanate (MDI) to generate a prepolymer (intermediate B) with a -NCO terminal, as shown in the following reaction formula: ; Step 13, silanization capping: A secondary aminosilane coupling agent (such as N-[3-(trimethoxysilyl)propyl]n-butylamine, SCA-A64M) is used to react with the -NCO group at the end of intermediate B to achieve silanization capping, yielding the target auxiliary resin TPMN. The reaction formula is as follows: .

[0033] The structural formula of the auxiliary resin TPMN prepared above is as follows: Its molecular structure is based on TMP, extending into three branches. Each branch is terminated by a trimethoxysilyl group via a urea bond, thus forming a star-shaped structure with high functionality, high viscosity, and high reactivity, as detailed below: .

[0034] This auxiliary resin has at least the following advantages: (1) High viscosity: Its star-shaped branched structure and high molecular weight give it high viscosity, which can significantly improve the overall viscosity of MS sealant and meet the anti-sagging requirements of vertical surface construction.

[0035] (2) High functionality: Each molecule has three highly active methoxysilyl groups at the end, which can participate more densely in the formation of cross-linking network during the curing process and greatly increase the sites for forming chemical bonds (Si-OM, M is metal) with the substrate surface, thereby significantly improving the adhesion strength to metal.

[0036] (3) Excellent compatibility: Its main chain is a polyether / urethane structure, which has excellent compatibility with the main body of silyl-terminated polyether resin, thus avoiding performance degradation caused by compatibility issues.

[0037] In some specific embodiments, the silane-terminated polyether resin in the above-mentioned sealant is a silane-terminated polyether with a viscosity of 5000–20000 mPa at 25°C. s; More preferably, the viscosity at 25°C is 10000–15000 mPa. The range of silyl-terminated polyether resins in this range ensures a high viscosity base and good curing crosslinking density for the sealant.

[0038] In some specific embodiments, the auxiliary resin in the above-mentioned sealant is selected from one or a combination of several of high-viscosity modified silane resin, terpene phenolic resin, polyallyl silane resin, and hydrogenated petroleum resin; more preferably, it is a high-viscosity modified silane resin. The auxiliary resin can synergistically increase the viscosity of the sealant and the number of active functional groups per unit area, thereby improving the initial tack and appropriately enhancing the interfacial adhesion.

[0039] In some specific embodiments, the low-viscosity polyether polyol in the above-mentioned sealant is a polyether with a number average molecular weight of 500-3000 and a viscosity of 50-500 mPa at 25°C. s, its function is to improve the processing fluidity of high viscosity systems without reducing the mechanical properties and adhesive strength of the sealant after curing.

[0040] In some specific embodiments, the dehydrating agent in the above-mentioned sealant is selected from one or more of vinyltrimethoxysilane, methyltrimethoxysilane, and phenyltrimethoxysilane; it has high dehydration efficiency and can synergistically crosslink with silane-terminated polyether resin, thereby improving the curing speed and density of the sealant.

[0041] In some specific embodiments, the antioxidant in the above-mentioned sealant is selected from one or a combination of antioxidant 1135, antioxidant 81, and antioxidant 93; it can effectively inhibit the oxidative aging of the sealant in high temperature and outdoor environments, and extend its service life.

[0042] In some specific embodiments, the silane coupling agent in the above-mentioned sealant is one or more of an aminosilane coupling agent or an epoxysilane coupling agent. The aminosilane coupling agent is selected from γ-aminopropyltriethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and the epoxysilane coupling agent is selected from γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane. The silane coupling agent can simultaneously react chemically with the hydroxyl groups on the aluminum surface and the polar groups on the electrophoretic steel coating to form a stable chemical bonding interface, significantly improving the bonding strength.

[0043] In some specific embodiments, the fumed silica powder in the above-mentioned sealant is hydrophobic fumed silica with a specific surface area of ​​150-200 m² / g, which can effectively improve the thixotropic properties and mechanical strength of the sealant and prevent the high viscosity system from sagging during construction.

[0044] In some specific embodiments, the plasticizer in the above-mentioned sealant is selected from one or more of diisononyl phthalate, dioctyl phthalate, and diisooctyl adipate; it has good compatibility with silane-terminated polyether resin and can improve the flexibility and low-temperature performance of the sealant.

[0045] In some specific embodiments, the nano-calcium carbonate in the above-mentioned sealant has a particle size of 10-100 nm and has undergone stearic acid surface modification treatment. It has good dispersibility and can form a good interfacial bond with the resin system, thereby improving the tensile strength and adhesive performance of the sealant.

[0046] In some specific embodiments, the ratio of the dehydrating agent to the coupling agent in the above-mentioned sealant is a certain ratio of 1:(1 to 2). Under this ratio, the sealant can better maintain the curing speed of the sealant itself and the speed of hydrolysis reaction between the sealant and the substrate surface.

[0047] In some specific embodiments, the catalyst in the above-mentioned sealant is selected from one or more of organotin catalysts and organobismuth catalysts; the catalyst can synergistically promote the hydrolysis and condensation reaction of silane groups, realize the rapid room temperature curing of the sealant, and the curing process is mild with no obvious exothermic phenomenon.

[0048] In some specific embodiments, the color paste in the above-mentioned sealant is an inorganic pigment color paste that is compatible with the sealant system. Different colors can be selected according to actual application requirements, and the amount added does not affect the curing performance and bonding performance of the sealant.

[0049] The present invention also provides a method for preparing the above-mentioned high-viscosity modified silane sealant, comprising the following steps: Step 1, Raw material pretreatment: Dry nano-calcium carbonate in an oven at 100-120℃ for 4-6 hours; dry fumed silica powder in an oven at 80-100℃ for 2-3 hours, and set aside. Step 2, base material preparation: Add silane-terminated polyether resin, auxiliary resin, low viscosity polyether, and antioxidant to the planetary stirred tank. Control the stirring speed at 20-60 r / min and the dispersion speed at 200-600 r / min. Stir for 10-40 minutes until a homogeneous base material is formed. Step 3, Powder mixing: Add the pretreated nano-calcium carbonate and color paste to the base material in step 2 in sequence. Control the stirring speed at 20-60 r / min and the dispersion speed at 200-600 r / min. Stir for 20-60 minutes to ensure that the filler is evenly dispersed. Step 4, Adding additives: Cool to 40-50℃, add dehydrating agent, antioxidant, and silane coupling agent to the mixture, stir while drawing a vacuum to -0.08 to -0.1MPa, control the stirring speed at 50-90 r / min, control the dispersion speed at 400-900 r / min, and stir for 5-20 minutes; Step 5, Catalysis and Discharge: Continue cooling to 30-40℃, add catalyst, stir while evacuating to a vacuum degree of -0.08 to -0.1MPa, control the stirring speed at 20-60 r / min, control the dispersion speed at 200-600 r / min, stir for 5-20 minutes to obtain high viscosity modified silane sealant.

[0050] The above-prepared sealant is then packaged in a sealed container under vacuum and stored in a cool, dark place.

[0051] In some specific embodiments, in the above method, the filler in step 3 is added in stages. After each filler is added, the mixture is stirred for 5 to 10 minutes, and the powder coating the planetary mixer wall and the paddle is scraped off. Stirring continues while vacuuming is performed. After the mixture is evenly stirred, the next filler is added to ensure that each filler is evenly dispersed in the base material and to avoid agglomeration.

[0052] In some specific embodiments, in the above method, in steps 3, 4, and 5, the inert gas introduced during vacuum release is nitrogen or argon to prevent the raw materials from oxidizing and deteriorating during stirring.

[0053] To more clearly demonstrate the technical solution and its effects provided by the present invention, the following detailed description of the solution provided by the embodiments of the present invention is provided with reference to specific examples.

[0054] Examples 1-3 and Comparative Examples 1-2: Sealant samples were prepared using the aforementioned preparation method according to the formulations (parts by weight) shown in Table 1 below.

[0055] Table 1 shows the formulations (parts by weight) for Examples 1-3 and Comparative Examples 1-2. .

[0056] Performance testing: The sealant samples prepared above were made into standard test pieces and tested according to the following standards: Viscosity: GB / T 10247, CAP2000+ cone-plate viscometer.

[0057] Tensile shear strength: GB / T 7124-2008, test substrates are 3003 aluminum-3003 aluminum, 6061 aluminum-6061 aluminum, 5083 aluminum-5083 aluminum, and electrophoretic steel-electrophoretic steel.

[0058] Hardness (Shore A): GB / T 531.1-2008.

[0059] Table 2 shows a comparison of performance test results. .

[0060] As clearly shown in Table 2, the sealants from Examples 1-3 using the self-synthesized auxiliary resin of this invention exhibit higher viscosity and hardness than the comparative examples, indicating that the system possesses higher initial strength and anti-sagging properties. Most importantly, on all tested metal substrates, the tensile shear strength of the examples is significantly superior to that of the comparative examples using commercially available SAXS750 and HF-D75, particularly demonstrating the most significant advantage in bonding strength to electrophoretic steel. This fully proves the superior effect of the self-synthesized auxiliary resin of this invention in improving bonding performance. This sealant exhibits high bonding strength to aluminum substrates and electrophoretic steel, making it particularly suitable for sealing applications requiring extremely high metal bonding strength and durability, such as new energy vehicle battery casings, automobile bodies, and transportation equipment.

[0061] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A high-viscosity modified silane sealant, characterized in that, Includes the following raw materials by weight: Silyl-terminated polyether resin: 10-50 parts; Auxiliary resin: 5-15 parts; Low viscosity polyether: 5-20 parts; Dehydrating agent: 0.5–3 parts; Antioxidant: 0.1 to 1 part; Silane coupling agent: 0.5–5 parts; Fumed silica powder: 1-5 parts; Plasticizer: 2-10 parts; Nano-calcium carbonate: 20-60 parts; Catalyst: 0.1–1 part; Color paste: 0.5 to 2 parts.

2. The high-viscosity modified silane sealant according to claim 1, characterized in that, The auxiliary resin is one or more of the following: high-viscosity modified silane resin, terpene phenolic resin, polyallyl silane resin, and hydrogenated petroleum resin.

3. The high-viscosity modified silane sealant according to claim 2, characterized in that, The high-viscosity modified silane resin is a high-viscosity modified silane resin with polymethoxysilane end groups synthesized in the following manner. Its molecular structure is based on TMP as the core, extending with three branches. Each branch end has a star-shaped structure with a trimethoxysilane group connected by a urea bond. The synthesis steps include: Step 21, Synthesis of intermediate A: Using trimethylolpropane as an initiator, ring-opening polymerization is carried out with propylene oxide in the presence of a catalyst to generate a trifunctional polyether triol as intermediate A, as shown in the following reaction formula; ； Step 12, Isocyanation: Intermediate A generated in Step 11 is reacted with excess diphenylmethane diisocyanate (MDI) to generate a prepolymer with a -NCO terminal, which serves as intermediate B. The reaction formula is as follows: ； Step 13, silanization capping: A secondary aminosilane coupling agent is used to react with the -NCO group at the end of intermediate B generated in step 12 to perform silanization capping, thus obtaining the auxiliary resin. The reaction formula is as follows: 。 4. The high-viscosity modified silane sealant according to any one of claims 1-3, characterized in that, The silane-terminated polyether resin is a silane-terminated polyether with a viscosity of 5000–20000 mPa at 25°C. s.

5. The high-viscosity modified silane sealant according to any one of claims 1-3, characterized in that, The low-viscosity polyether polyol is a polyether polyol with a number average molecular weight of 500-3000 and a viscosity of 50-500 mPa at 25°C. s; The dehydrating agent is one or more of vinyltrimethoxysilane, methyltrimethoxysilane, and phenyltrimethoxysilane; The antioxidant is one or more of antioxidant 1135, antioxidant 81, and antioxidant 93.

6. The high-viscosity modified silane sealant according to any one of claims 1-3, characterized in that, The alkyl coupling agent is one or more of aminosilane coupling agents and epoxysilane coupling agents.

7. The high-viscosity modified silane sealant according to claim 6, characterized in that, The aminosilane coupling agent is one of γ-aminopropyltriethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; The epoxy silane coupling agent is one of γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane.

8. The high-viscosity modified silane sealant according to any one of claims 1-3, characterized in that, The fumed silica powder is hydrophobic fumed silica with a specific surface area of ​​150-200 m² / g; The plasticizer is one or more of diisononyl phthalate, dioctyl phthalate, and diisooctyl adipate. The nano-calcium carbonate used is nano-calcium carbonate with a particle size of 10-100 nm and has undergone stearic acid surface modification treatment. The catalyst is one or more of organotin catalysts and organobismuth catalysts; The color paste is an inorganic pigment color paste.

9. A method for preparing the high-viscosity modified silane sealant according to any one of claims 1-8, characterized in that, The raw materials are prepared according to the formula according to any one of claims 1-8, including the following steps: Step 1, raw material pretreatment: Place the nano-calcium carbonate in the raw material in an oven at 100-120℃ and dry for 4-6 hours; place the fumed silica powder in an oven at 80-100℃ and dry for 2-3 hours, then set aside. Step 2, base material preparation: Add the terminal silane polyether resin, auxiliary resin, low viscosity polyether and antioxidant from the raw materials to the planetary stirred tank. Control the stirring speed at 20-60 r / min and the dispersion speed at 200-600 r / min. Stir for 10-40 minutes until a homogeneous base material is formed. Step 3, Powder mixing: Add color paste and pretreated nano-calcium carbonate to the base material obtained in Step 2 in sequence. Control the stirring speed at 20-60 r / min and the dispersion speed at 200-600 r / min. Stir for 20-60 minutes to ensure that the nano-calcium carbonate and color paste filler are evenly dispersed to obtain a mixture. Step 4, Adding additives: Cool to 40-50℃, add dehydrating agent, antioxidant and silane coupling agent to the mixture obtained in step 3, stir and evacuate to a vacuum degree of -0.08 to -0.1MPa, control the stirring speed at 50-90 r / min, control the dispersion speed at 400-900 r / min, stir for 5-20 minutes; Step 5, Catalysis and Discharge: Continue cooling to 30-40℃, add catalyst to the reactants in Step 4, stir while evacuating to a vacuum degree of -0.08 to -0.1MPa, control the stirring speed at 20-60 r / min, control the dispersion speed at 200-600 r / min, stir for 5-20 minutes to obtain high viscosity modified silane sealant.

10. The method for preparing the high-viscosity modified silane sealant according to claim 9, characterized in that, In step 3, the filler is added in stages. After each filler is added, the mixture is stirred for 5 to 10 minutes, and the paddle is scraped off the powder coating the planetary mixer wall and the paddle. Stirring continues while vacuuming is performed. After the mixture is evenly stirred, the next filler is added so that each filler can be evenly dispersed in the base material. In steps 3, 4, and 5, the inert gas introduced during vacuum release is nitrogen or argon.

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