Low modulus and high elongation antifouling and weather-resistant sealant, preparation method and application thereof

Abstract

The present invention belongs to the field of sealant technology and discloses a low-modulus, high-elongation antifouling and weather-resistant sealant, a preparation method, and its application. The sealant comprises the following raw materials in parts by weight: 100 parts of α,ω-dihydroxy polysiloxane, 80-200 parts of inorganic filler, 10-30 parts of cross-linking agent, 1-4 parts of coupling agent, and 2-10 parts of titanate vulcanizer; wherein the inorganic filler comprises activated calcium carbonate and modified talc; the modified talc is prepared by sequentially flaking and modifying talc. The low-modulus, high-elongation antifouling sealant provided by the present invention is well suited for sealing joints during the restoration of ancient buildings. The product can also be extended to other fields of building seals that also require low-modulus antifouling, and has high economic value.

Description

Technical Field

[0001] The present invention relates to the technical field of sealants, and in particular to a low-modulus and high-elongation anti-fouling and weather-resistant sealant, a preparation method and application thereof. Background Art

[0002] Silicone materials are widely used in construction, aerospace, electrical and electronic insulation and sealing, rail transit, and cultural relic preservation and restoration. In the building sealing field, silicone sealants, due to their excellent resistance to UV aging, high and low temperatures, and fatigue, are often used for structural bonding and joint sealing of doors, windows, and curtain walls, providing waterproofing, moisture resistance, thermal insulation, and noise reduction.

[0003] In the restoration of ancient buildings, most are wooden or stone buildings. Due to the mortise and tenon structure and the fragility of wooden materials, wooden buildings need to meet a higher displacement level when sealing the joints, and at the same time, they need to withstand less stress in order to play a protective and sealing role. In the restoration of ancient buildings, it is also necessary to follow the principle of authentic restoration, and the modern materials used cannot corrode or pollute the ancient buildings.

[0004] Currently, sealants with low modulus and high elongation on the market often contain a large amount of low-molecular-weight plasticizers. Such plasticizers easily migrate and seep into the sealant system, causing contamination. Other sealants with anti-fouling properties have high bonding strength, but excessive stress can damage the building substrate, thereby affecting the sealing effect. For example, patent No. CN113528080 B discloses a high-displacement anti-fouling silicone sealant and its preparation method. Although it has good displacement ratings and anti-fouling properties, its stress strength is not mentioned. Furthermore, the ketoxime additive used is corrosive to the building substrate and cannot be used for the restoration of ancient buildings. Patent No. CN114507504 B discloses a low-modulus, high-elongation, one-component silicone sealant and its application. This low-modulus, high-elongation sealant is developed using a capped polymer, but the system still requires the addition of a large amount of methyl silicone oil plasticizer, making the sealant somewhat polluting and unsuitable for the restoration of ancient buildings.

[0005] Therefore, the development of a low-modulus, high-elongation anti-fouling sealant can be better suited for joint sealing during the restoration of ancient buildings. At the same time, this product can also be extended to other fields that also require low-modulus anti-fouling building sealing, and has high economic value. Summary of the Invention

[0006] In view of the above-mentioned shortcomings that currently exist, the present invention provides a low-modulus, high-elongation anti-fouling and weather-resistant sealant, a preparation method and its application. The present invention performs layered exfoliation and modification treatment on talc powder, so that the talc powder has good compatibility and interlayer displacement, effectively reducing the internal stress inside the sealant, so that the sealant has low modulus strength and high elongation, which can effectively reduce the stress between fragile structures when sealing joints and protect buildings from damage; the present invention uses silane oligomers as cross-linking agents, and adjusts the cross-linking density in the system to further improve the elongation and reduce the modulus. At the same time, the present invention does not use various plasticizers and small molecule cross-linking agents, and even in the initial stage of curing, the seepage of highly active small molecule substances to form swelling, corrosion and pollution is avoided; the curing system adopts a dealcoholized sealant, and the released small molecule alcohol substances are non-corrosive to various substrates and are environmentally friendly.

[0007] In order to achieve the above objectives, in a first aspect, the present invention provides a low modulus and high elongation anti-fouling and weather-resistant sealant, comprising the following raw materials in parts by weight:

[0008] 100 parts of α,ω-dihydroxy polysiloxane, 80-200 parts of inorganic filler, 10-30 parts of crosslinking agent, 1-4 parts of coupling agent, 2-10 parts of titanate vulcanizing agent;

[0009] Wherein, the inorganic filler includes activated calcium carbonate and modified talc;

[0010] The modified talc powder is prepared by sequentially subjecting talc powder to layered flaking and modification treatments; the modified talc powder comprises the following raw materials in parts by weight:

[0011] Talc: 0-20 parts; mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate: 100 parts; modifier 1: 0.01-0.2 parts; modifier 2: 0.1-1 parts.

[0012] Wherein, the mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate has a pH value of 10.

[0013] Furthermore, the weight ratio of the activated calcium carbonate and the modified talc is (40-150) / (40-100); the modifier 1 is at least one of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(N-cyclohexylamino)propylmethyldimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-(methacryloyloxy)propylmethyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane; and the modifier 2 is at least one of stearic acid (salt), rosin acid (salt), coconut oil, palmitic acid (salt), gum arabic, and tannic acid.

[0014] Furthermore, the layered exfoliation step is specifically as follows: adding talc powder to a mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate and vigorously stirring, then subjecting the mixture to hydrothermal reaction, solid-liquid separation, washing the solid product, and drying to obtain intercalated talc powder.

[0015] Furthermore, the modification treatment step is specifically as follows: dissolving the intercalated talc powder in water, adding modifier 1, stirring and dispersing at 50-80°C for 50-120 minutes, then adding modifier 2, stirring and dispersing at 60-80°C for 90-180 minutes, and then performing solid-liquid separation, washing the solid product, and drying to obtain modified talc powder;

[0016] Furthermore, the temperature of the hydrothermal reaction is 50-80° C., and the reaction time is 50-180 min.

[0017] Furthermore, the viscosity of the α,ω-dihydroxy polysiloxane at 25° C. is 5000 mPa.s to 150000 mPa.s.

[0018] Furthermore, the crosslinking agent is at least one of vinylmethoxysilane oligomer, vinylethoxysilane oligomer, and vinylmethoxyethoxysilane oligomer; the coupling agent is at least one of aminosilane polymer, epoxysilane oligomer, and acyloxysilane oligomer; and the titanate vulcanizing agent is diisopropoxytitanium bis(ethyl acetoacetate) chelate.

[0019] In a second aspect, the present invention provides a method for preparing the above-mentioned low modulus and high elongation antifouling and weather-resistant sealant, comprising the following steps:

[0020] S1, α,ω-dihydroxy polysiloxane, nano calcium carbonate, and modified talc are added to a kneader at a temperature of 80-150°C and a vacuum degree of 0.06-0.099 MPa, and dehydrated and blended for 30-300 minutes, and then cooled to obtain a base material;

[0021] S2. At room temperature, the base material is added into a planetary mixer or a high-speed disperser, and then the crosslinking agent is added into the planetary mixer or the high-speed disperser, with a vacuum degree of 0.06 to 0.099 MPa, a rotation speed of 10 to 800 rpm, and a stirring time of 10 to 30 min. Then, the coupling agent and the phthalate vulcanizing agent are added into the planetary mixer or the high-speed disperser, and a chemical reaction is carried out for 30 to 180 min at a vacuum degree of 0.06 to 0.099 MPa and a rotation speed of 10 to 800 rpm to obtain a low modulus and high elongation antifouling sealant.

[0022] In a third aspect, the present invention further provides the use of the above-mentioned low modulus and high elongation antifouling and weather-resistant sealant in sealing low modulus antifouling building joints.

[0023] Furthermore, the low modulus anti-fouling building joint sealing is used for joint sealing during the restoration of ancient buildings.

[0024] The modification principle of the modified talc powder of the present invention is as follows: Modifier 1 is a coupling agent with difunctionality, which reacts with the hydroxyl groups on the surface of the talc powder to provide certain reactive sites on the surface of the talc powder, which can improve the bonding strength between the powder and the polymer and increase the elongation. At the same time, the difunctionality of the crosslinking sites can effectively control the crosslinking density, reduce the cohesion and control the modulus growth. Modifier 2 acts as a coating agent, making the modified powder surface hydrophilic / oleophilic, which can improve the compatibility of the powder with the polymer (coating with modifier 2 first and then modifying with modifier 1 will seriously affect the modification effect of modifier 1).

[0025] Beneficial effects of the present invention:

[0026] (1) The present invention applies layered flaking and modification to the talc powder (modified talc powder), which can reduce internal stress, softening the rubber strip and lowering the modulus. When subjected to external pressure, the sliding between the modified talc powder layers can effectively absorb energy, effectively improving elongation. At the same time, the modification also improves the compatibility and mechanical properties of the powder with the polymer, making the system more stable.

[0027] (2) The present invention uses silane oligomers as crosslinking agents, which can adjust the crosslinking density in the system. The powder modification further improves the elongation of the sealant and reduces the modulus.

[0028] (3) The system of the present invention does not use various plasticizers, which can effectively prevent contamination caused by plasticizer migration. At the same time, the oligomeric cross-linking agent used prevents the auxiliary agent from migrating rapidly in the early stage of curing, thereby reducing the foaming and corrosion caused by poor compatibility with the substrate surface, especially the porous wooden substrate;

[0029] (4) The present invention adopts a dealcoholization system, and the small molecule alcohol substances released during the curing process are relatively environmentally friendly, low in toxicity and non-corrosive. DETAILED DESCRIPTION

[0030] To make the present invention easier to understand, the present invention is further described below with reference to specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professional and technical personnel in this field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by known methods.

[0031] Example 1

[0032] A method for preparing a low-modulus, high-elongation anti-fouling and weather-resistant sealant:

[0033] (1) Preparation method of modified talc

[0034] a. Take 20 parts of talc and add 100 parts of a mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate (pH = 10) and stir vigorously. After hydrothermal reaction at 80 ° C for 2h, the solid product is collected by solid-liquid separation, washed and dried to obtain intercalated talc.

[0035] b. Take 20 parts of the intercalated talc, add 50 parts of water and stir and disperse, add 0.1 parts of 3-aminopropylmethyldimethoxysilane, continue stirring and dispersing at 60 ° C for 1h, add 0.5 parts of sodium stearate, continue stirring and dispersing at 60 ° C for 2h, perform solid-liquid separation and collect the solid product, wash and dry to obtain modified talc.

[0036] (2) Preparation method of low modulus and high elongation anti-fouling and weather-resistant sealant

[0037] A. Take 80 parts of α, ω-dihydroxy polysiloxane (50000 mPa.s) and 100 parts of nano calcium carbonate / modified talc (mass ratio 3:2) and add them to a kneader. The temperature is 120°C and the vacuum degree is -0.099 MPa. Dehydrate and blend for 120 minutes. After cooling, the base material is obtained.

[0038] B. At room temperature, add the above base material into a planetary mixer or a high-speed disperser, then add 20 parts of vinylmethoxysilane oligomer into the planetary mixer or high-speed disperser, vacuum degree -0.06MPa, rotation speed 400rpm, stirring time 10 minutes, then add 3 parts of coupling agent (the mass ratio of aminosilane polymer to epoxysilane oligomer is 2:1) and 5 parts of diisopropoxytitanium bis(ethyl acetoacetate) chelate into the planetary mixer or high-speed disperser at a vacuum degree -0.099MPa and a rotation speed of 400rpm for chemical reaction for 45 minutes to prepare a low modulus and high elongation anti-fouling sealant.

[0039] Example 2

[0040] A method for preparing a low-modulus, high-elongation anti-fouling and weather-resistant sealant:

[0041] (1) Preparation method of modified talc

[0042] a. Take 20 parts of talc and add 100 parts of a mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate (pH = 10) and stir vigorously. After hydrothermal reaction at 80 ° C for 2h, the solid product is collected by solid-liquid separation, washed and dried to obtain intercalated talc.

[0043] b. Take 20 parts of the above talc, add 50 parts of water and stir and disperse, add 0.1 parts of 3-(N-cyclohexylamino)propylmethyldimethoxysilane, continue stirring and dispersing at 60°C for 1h, add 0.5 parts of sodium palmitate, continue stirring and dispersing at 60°C for 2h, perform solid-liquid separation and collect the solid product, wash and dry to obtain modified talc.

[0044] (2) Preparation method of low modulus and high elongation anti-fouling and weather-resistant sealant

[0045] A. Take 80 parts of α,ω-dihydroxy polysiloxane (12000-50000 mPa.s) and 100 parts of nano calcium carbonate / modified talc (mass ratio 3:2) and add them to a kneader. The temperature is 120°C and the vacuum degree is -0.099 MPa. Dehydrate and blend for 120 minutes. After cooling, the base material is obtained.

[0046] B. At room temperature, add the above base material into a planetary mixer or a high-speed disperser, then add 20 parts of vinylethoxysilane oligomer into the planetary mixer or high-speed disperser, vacuum degree 0.06MPa, rotation speed 400rpm, stirring time 10 minutes, then add 3 parts of coupling agent (the mass ratio of aminosilane polymer to epoxysilane oligomer is 2:1) and 5 parts of diisopropoxytitanium bis(ethyl acetoacetate) chelate into the planetary mixer or high-speed disperser at a vacuum degree of -0.099MPa and a rotation speed of 400rpm for chemical reaction for 45 minutes to prepare a low modulus and high elongation anti-fouling sealant.

[0047] Example 3

[0048] A method for preparing a low-modulus, high-elongation anti-fouling and weather-resistant sealant:

[0049] (1) Preparation method of modified talc

[0050] a. Take 10 parts of talc and add 100 parts of a mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate (pH = 10) and stir vigorously. After hydrothermal reaction at 80 ° C for 2h, the solid product is collected by solid-liquid separation, washed and dried to obtain intercalated talc.

[0051] b. Take 20 parts of the above talc, add 50 parts of water and stir and disperse, add 0.2 parts of 3-glycidyloxypropylmethyldimethoxysilane, continue stirring and dispersing at 60 ° C for 1h, add 0.5 parts of rosin acid, continue stirring and dispersing at 60 ° C for 2h, perform solid-liquid separation and collect the solid product, wash and dry to obtain modified talc.

[0052] (2) Preparation method of low modulus and high elongation anti-fouling and weather-resistant sealant

[0053] A. Take 100 parts of α,ω-dihydroxy polysiloxane (12000-50000 mPa.s) and 100 parts of nano calcium carbonate / modified talc (mass ratio 3:2) and add them to a kneader. The temperature is 120°C and the vacuum degree is -0.099 MPa. Dehydrate and blend for 120 minutes. After cooling, the base material is obtained.

[0054] B. At room temperature, add the above base material into a planetary mixer or a high-speed disperser, then add 20 parts of vinyl methoxyethoxy silane oligomer into the planetary mixer or high-speed disperser, vacuum degree -0.06MPa, rotation speed 400rpm, stirring time 10 minutes, then add 3 parts of coupling agent (the mass ratio of aminosilane polymer to acyloxysilane oligomer is 2:1) and 5 parts of diisopropoxy titanium bis (ethyl acetoacetate) chelate into the planetary mixer or high-speed disperser at a vacuum degree of -0.099MPa and a rotation speed of 400rpm for chemical reaction for 45 minutes to prepare a low modulus and high elongation anti-fouling sealant.

[0055] Example 4

[0056] A method for preparing a low-modulus, high-elongation anti-fouling and weather-resistant sealant:

[0057] (1) Preparation method of modified talc

[0058] a. Take 20 parts of talc and add 100 parts of a mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate (pH = 10) and stir vigorously. After hydrothermal reaction at 80 ° C for 2h, the solid product is collected by solid-liquid separation, washed and dried to obtain intercalated talc.

[0059] b. Take 20 parts of the above talc, add 50 parts of water and stir and disperse, add 0.1 parts each of 3-glycidyloxypropylmethyldiethoxysilane and 3-(methacryloyloxy)propylmethyldiethoxysilane, continue stirring and dispersing at 60°C for 1h, add 0.5 parts of stearic acid, continue stirring and dispersing at 60°C for 2h, perform solid-liquid separation and collect the solid product, wash and dry to obtain modified talc.

[0060] (2) Preparation method of low modulus and high elongation anti-fouling and weather-resistant sealant

[0061] A. Take 80 parts of α, ω-dihydroxy polysiloxane (12000-50000 mPa.s) and 100 parts of nano calcium carbonate / modified talc (mass ratio 1:1) and add them to a kneader. The temperature is 120°C and the vacuum degree is -0.099 MPa. Dehydrate and blend for 120 minutes. After cooling, the base material is obtained.

[0062] B. At room temperature, add the above base material into a planetary mixer or a high-speed disperser, then add 20 parts of vinylethoxysilane oligomer into the planetary mixer or high-speed disperser, vacuum degree -0.06MPa, rotation speed 400rpm, stirring time 10 minutes, then add 3 parts of coupling agent (the mass ratio of aminosilane polymer to acyloxysilane oligomer is 1:1) and 5 parts of diisopropoxytitanium bis(ethyl acetoacetate) chelate into the planetary mixer or high-speed disperser at a vacuum degree of -0.099MPa and a rotation speed of 400rpm for chemical reaction for 45 minutes to prepare a low modulus and high elongation anti-fouling sealant.

[0063] Example 5

[0064] A method for preparing a low-modulus, high-elongation anti-fouling and weather-resistant sealant:

[0065] (1) Preparation method of modified talc

[0066] a. Take 10 parts of talc and add 100 parts of a mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate (pH = 10) and stir vigorously. After hydrothermal reaction at 80 ° C for 2h, the solid product is collected by solid-liquid separation, washed and dried to obtain intercalated talc.

[0067] b. Take 20 parts of the above talc, add 50 parts of water and stir and disperse, add 0.2 parts of 3-(methacryloyloxy)propylmethyldimethoxysilane, continue stirring and dispersing at 60 ° C for 1h, add 0.5 parts of tannic acid, continue stirring and dispersing at 60 ° C for 2h, perform solid-liquid separation and collect the solid product, wash and dry to obtain modified talc

[0068] (2) Preparation method of low modulus and high elongation anti-fouling and weather-resistant sealant

[0069] A. Take 100 parts of α,ω-dihydroxy polysiloxane (50000 mPa.s) and 100 parts of nano calcium carbonate / modified talc (mass ratio 1:1) and add them to a kneader. The temperature is 120°C and the vacuum degree is -0.099 MPa. Dehydrate and blend for 120 minutes. After cooling, the base material is obtained.

[0070] B. At room temperature, add the above base material into a planetary mixer or a high-speed disperser, then add 20 parts of vinylethoxysilane oligomer into the planetary mixer or high-speed disperser, vacuum degree -0.06MPa, rotation speed 400rpm, stirring time 10 minutes, then add 3 parts of coupling agent (the mass ratio of aminosilane polymer to acyloxysilane oligomer is 1:1) and 5 parts of diisopropoxytitanium bis(ethyl acetoacetate) chelate into the planetary mixer or high-speed disperser at a vacuum degree of -0.099MPa and a rotation speed of 400rpm for chemical reaction for 45 minutes to prepare a low modulus and high elongation anti-fouling sealant.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 1 is that modified talc is not used. Other aspects are the same as Example 1.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that 20 parts of dimethyl silicone oil are added to the silicone sealant, 20 parts of methyltrimethoxysilane are used, and 3 parts of coupling agent (γ-aminopropylethoxysilane: epoxypropyltriethoxysilane = 2:1) are used. Other procedures are the same as in Example 1.

[0075] Comparative Example 3

[0076] The difference between this comparative example and Example 1 is that the modified talc powder is only subjected to stratification and exfoliation without modification.

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 1 is that the modified talc powder is not subjected to stratification and exfoliation, but only subjected to modification treatment.

[0079] Performance testing and result analysis:

[0080] Test method for mechanical properties of silicone sealant: The test is carried out in accordance with the provisions and standards of GB / T14683-2017 "Silicone and modified silicone building sealants". The tensile adhesion is tested in accordance with GB / T13477.8-2017 "Test methods for building sealing materials". The contamination test is carried out in accordance with the standard method in Appendix A of GB / T 23261-2009 "Building sealants for stone".

[0081] The compatibility test between the sealant and the substrate surface during the initial curing phase was conducted on a smooth, untreated natural granite surface. The test method involved applying the sealant to the granite surface, creating a thin sheet measuring 100 x 50 x 3 mm in length, width, and height. Without demolding, the sealant was immediately placed in a 70°C oven for accelerated curing for 24 hours. Finally, the granite surface was observed for small bubbles or bulges. The test results are shown in Table 1 below:

[0082] Table 1:

[0083]

[0084] Note: S1, S2, S3, S4, and S5 in Table 1 refer to Example 1, Example 2, Example 3, Example 4, and Example 5 respectively; D1, D2, D3, and D4 refer to Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 respectively.

[0085] As can be seen from Table 1 above, the talc powder in Examples 1 to 5 can effectively reduce the cohesive force after exfoliation and modification, so that the sealant has a lower modulus and higher elongation. The modulus reduction effect of the talc powder varies depending on the treatment agent. At the same time, the solution concentration used for exfoliation and the glue / powder ratio used in the preparation of the sealant will also slightly affect the performance. However, overall, the low modulus, high elongation and anti-fouling requirements can be well achieved. In Comparative Example 1, the modulus is significantly improved without using talcum powder. This is because the reinforcing ability of pure nano calcium carbonate is good, and the cohesive force is too high, which causes the rubber strip to harden. Although modified talcum powder is used in Comparative Example 2, the selected small molecule additive has a higher molar mass than the oligomeric cross-linking agent at the same weight, resulting in a higher cross-linking density. The modulus is 0.45MPa when silicone oil is added, which is the upper limit of the low modulus. At the same time, the addition of silicone oil also leads to pollution. After using the low molecular cross-linking agent, the compatibility with the stone becomes worse, and there is slight foaming. Comparative Examples 3 and 4 are modified and intercalated, respectively, and Comparative Example 3 without modification This makes the compatibility of the powder with polysiloxane worse, and the reinforcement effect, thixotropy and elastic recovery rate all worse. Although the modulus is lower than that of Comparative Example 1, it still has a high modulus, and the displacement level also fails to meet the requirement of level 50; and Comparative Example 4 does not undergo talcum powder exfoliation and layering treatment. Although its strength is low, its elastic recovery rate is poor, which easily leads to the sealant being unable to rebound and lose its sealing performance. This situation is mainly caused by the original talcum powder crystals being too thick, and the interlayer sliding after being stressed is too large, resulting in the crystal form being destroyed and unable to recover, thereby affecting the overall elasticity of the sealant. It is necessary to reduce the crystal thickness and control the deformation through exfoliation and layering treatment.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A low modulus and high elongation antifouling and weather-resistant sealant, characterized in that: The raw materials include the following parts by weight: 100 parts of α,ω-dihydroxy polysiloxane, 80-200 parts of inorganic filler, 10-30 parts of crosslinking agent, 1-4 parts of coupling agent, 2-10 parts of titanate vulcanizing agent; The crosslinking agent is at least one of vinylmethoxysilane oligomer, vinylethoxysilane oligomer, and vinylmethoxyethoxysilane oligomer; the coupling agent is at least one of aminosilane polymer, epoxysilane oligomer, and acyloxysilane oligomer; the titanate vulcanizing agent is diisopropoxytitanium bis(ethyl acetoacetate) chelate; the inorganic filler includes activated calcium carbonate and modified talc; the weight ratio of the activated calcium carbonate to the modified talc is (40-150) / (40-100); The modified talc powder is prepared by sequentially subjecting talc powder to layered flaking and modification treatments; the modified talc powder comprises the following raw materials in parts by weight: Talc: 0-20 parts; mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate: 100 parts; modifier 1: 0.01-0.2 parts; modifier 2: 0.1-1 parts; the modifier 1 is at least one of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(N-cyclohexylamino)propylmethyldimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-(methacryloyloxy)propylmethyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane; the modifier 2 is at least one of stearic acid, stearate, rosin acid, rosin acid, palmitic acid, palmitate, and tannic acid.

2. The low modulus and high elongation antifouling and weather-resistant sealant according to claim 1, characterized in that: The layered exfoliation step specifically comprises: adding talc powder to a mixed solution of sodium hydroxide and sodium dodecylbenzenesulfonate and vigorously stirring, then subjecting the mixture to hydrothermal reaction, solid-liquid separation, washing the solid product, and drying to obtain intercalated talc powder.

3. The low modulus and high elongation antifouling and weather-resistant sealant according to claim 2, characterized in that: The modification treatment steps are specifically as follows: dissolving the intercalated talc powder in water, adding modifier 1, stirring and dispersing at 50-80°C for 50-120 minutes, then adding modifier 2, stirring and dispersing at 60-80°C for 90-180 minutes, and then performing solid-liquid separation, washing the solid product, and drying to obtain the modified talc powder.

4. The low modulus and high elongation antifouling and weather-resistant sealant according to claim 2, characterized in that: The temperature of the hydrothermal reaction is 50-80° C., and the reaction time is 50-180 min.

5. The low modulus and high elongation antifouling and weather-resistant sealant according to claim 1, characterized in that: The viscosity of the α,ω-dihydroxy polysiloxane at 25° C. is 5000 mPa.s to 150000 mPa.s.

6. The method for preparing the low modulus and high elongation antifouling and weather-resistant sealant according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, α,ω-dihydroxy polysiloxane, nano calcium carbonate, and modified talc are added to a kneader at a temperature of 80-150°C and a vacuum degree of 0.06-0.099 MPa, and dehydrated and blended for 30-300 minutes, and then cooled to obtain a base material; S2. At room temperature, the base material is added into a planetary mixer or a high-speed disperser, and then the crosslinking agent is added into the planetary mixer or the high-speed disperser with stirring, the vacuum degree is 0.06-0.099 MPa, the rotation speed is 10-800 rpm, and the stirring time is 10-30 min. Then, the coupling agent and the phthalate vulcanizing agent are added into the planetary mixer or the high-speed disperser, and the chemical reaction is carried out for 30-180 min at a vacuum degree of 0.06-0.099 MPa and a rotation speed of 10-800 rpm to obtain a low modulus and high elongation antifouling sealant.

7. Use of the low modulus, high elongation antifouling and weather-resistant sealant according to any one of claims 1 to 5 or the low modulus, high elongation antifouling and weather-resistant sealant prepared by the preparation method according to claim 6 in sealing low modulus antifouling building joints.

8. The use according to claim 7, characterized in that The low-modulus anti-fouling building joint sealing is used for joint sealing during the restoration of ancient buildings.

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