Modified polyether as well as preparation method and application thereof

Abstract

The invention provides modified polyether as well as a preparation method and application thereof. The preparation method of the modified polyether comprises the following steps: S1, under the protection of nitrogen, mixing carbonic ester, aminoalkyl silane and a first catalyst, adjusting the pH value to be neutral after the reaction is finished, and collecting carbamate silane; s2, under the protection of nitrogen, mixing the product obtained in the step S1 with single-ended allyl polyoxypropylene ether, removing unreacted alcohol and amino-acid ester silane after the reaction is finished, and cooling to room temperature under the protection of nitrogen to obtain a product; and S3, under the protection of nitrogen, mixing the product obtained in S2, a double-end hydrogen-containing silane compound and a second catalyst, reacting at 75-90 DEG C for 2-3 hours, adding activated carbon, and carrying out hot filtration, thereby obtaining the product, the second catalyst is vinyl silane platinum. The modified polyether provided by the invention can enable the sealant to have good tensile property and deep curing property in the sealant.

Description

Technical Field

[0001] The present invention relates to the technical field of modified polyether synthesis, and more specifically, to a modified polyether and a preparation method and application thereof. Background Art

[0002] Sealant is widely used in various applications due to its excellent performance, such as filling gaps, waterproofing, heat insulation, earthquake resistance, etc. Sealant includes polysulfide sealant, silicone sealant, polyurethane sealant, silane-modified sealant, etc. Silane-modified sealant was originally an elastic sealant based on end-capped alkyl polyether. Later, it was quickly favored by researchers in various countries due to its special performance. To date, researchers call the one-component or two-component elastic sealant prepared with end-silane polyether (MS) as the base polymer and other fillers and additives silane-modified polyether glue (MS glue), which is mainly used in the fields of bonding, caulking, sealing, waterproofing, reinforcement, containers, elevator industry, etc. in construction engineering and decoration.

[0003] Although MS glue has so many excellent properties, it still has many defects in specific application fields. For example, the heat resistance of sealants. When silane-modified polyether sealants are prepared with polyether polyols as raw materials, to obtain high molecular weight polyethers, it is usually necessary to use low molecular weight polyether polyols to extend the chain to meet the requirements of polyether glue for base glue molecular weight and strength during application. However, when using commonly used chain extenders, there are more by-products during chain extension, and the chain itself is short and has poor temperature resistance, which only has the effect of chain extension but cannot improve the heat resistance of polyether. The R&D team provided a preparation method with a specific sequence to address this problem, and used a specific chain extender such as a double-terminal hydrogen-containing silane compound to effectively improve the heat resistance and tensile properties of MS glue. However, the applicant later discovered that the silane-modified polyether prepared by the addition of trimethoxyhydrogen-containing silane has the problem that trimethoxyhydrogen-containing silane is highly active and easily disproportionated, the catalyst is easily deactivated, the obtained silane-modified polyether product has a dark color, the silane end-capping modification is incomplete, and the sealant has poor moisture depth curing. Summary of the invention

[0004] In order to solve or at least partially solve the problems in the prior art, the present invention provides a modified polyether and a preparation method thereof. The modified polyether obtained by the preparation method provided by the present invention can make the sealant have both good tensile properties and deep curing properties.

[0005] The preparation method of the modified polyether provided by the present invention comprises the following steps:

[0006] S1, under nitrogen protection, carbonate, aminosilane and a first catalyst are mixed, reacted under reflux until the content of aminosilane in the system is ≤0.3%, after the reaction is completed, the pH value of the system is adjusted to 6-7, and the carbamate silane is collected at 140-160° C. and -0.07--0.08 MPa; the first catalyst is an alkali metal, a transition metal, an alkali metal oxide or a saturated alcohol solution of an alkali metal;

[0007] S2, under nitrogen protection, mixing the carbamate silane obtained in step S1 with the single-end allyl polyoxypropylene ether, distilling and dealcoholizing under reflux until no obvious fraction is produced, removing unreacted carbamate silane, and cooling the temperature to room temperature under nitrogen protection to obtain a product;

[0008] S3, under nitrogen protection, mixing the product obtained in step S2, the double-terminal hydrogen-containing silane compound and the second catalyst, reacting at 75-90° C. for 2-3 hours, adding activated carbon for treatment for 0.5-1 hour after the reaction, and filtering hot to obtain the product; the second catalyst is vinyl silane platinum.

[0009] In a preferred embodiment of the present invention, in step S1, the carbonate is dimethyl carbonate, diethyl carbonate or dipropyl carbonate, preferably dimethyl carbonate. In the present invention, the applicant has found that carbonate is easy to absorb water. In order to obtain a solution that can achieve the purpose of the present invention, the water content in the raw material carbonate acid needs to be controlled below 500ppm before use.

[0010] In a preferred embodiment of the present invention, in order to further improve the performance of the sealant, in step S1, the aminoalkylsilane is γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, or γ-n-butylaminopropyltrimethoxysilane or piperazinylpropyltrimethoxysilane, preferably γ-aminopropyltrimethoxysilane (also known as aminopropyltrimethoxysilane). The applicant has found that when γ-aminopropyltrimethoxysilane is selected as the aminoalkylsilane and reacted with other components under a specific preparation method, the performance of the obtained sealant is the best.

[0011] In a preferred embodiment of the present invention, in step S1, the molar ratio of carbonate to aminosilane is (1.8-2.2):1.

[0012] In the present invention, the first catalyst in step S1 can be an alkali metal, a transition metal, an alkali metal oxide, a saturated alcohol solution of an alkali metal, etc., preferably a saturated alcohol solution of an alkali metal, and more preferably a saturated solution of sodium methoxide / methanol. In a specific embodiment of the present invention, the concentration of the saturated alcohol solution of the alkali metal is 10 to 30%, and in a preferred embodiment, the concentration of the saturated solution of sodium methoxide / methanol can be 29 to 29.5%. In a specific embodiment of the present invention, the amount of the first catalyst in step S1 is preferably 0.2% to 0.5% of the total mass of the carbonate and aminohydrocarbylsilane (i.e., the total mass of the system raw materials (excluding the catalyst)).

[0013] In a specific embodiment of the present invention, in step S1, the reflux temperature is 80-85° C. After the reaction is completed, the pH value of the system is usually adjusted to 6-7 after the system temperature drops to room temperature, and preferably a neutralizer is used to adjust the pH value of the system to 6-7. Among them, the neutralizer is preferably an organic acid such as acetic acid, oxalic acid, or other inorganic acid that can treat the pH to 6-7 without causing hydrolysis reaction between silane and the product, and acetic acid is more preferably used.

[0014] In a preferred embodiment of the present invention, in step S1, after the pH value of the system is adjusted to 6 to 7, atmospheric distillation can be carried out at 100 to 130° C. until no fraction is produced, and then the temperature is reduced to 70 to 90° C., and the unreacted carbonate is recovered at -0.04 to -0.06 MPa, and then the carbamate silane is collected at 140 to 160° C. and -0.07 to -0.08 MPa.

[0015] In step S2 of the present invention, the single-end allyl polyoxypropylene ether (APPG-OH) also needs to be dehydrated to a moisture content of <500ppm before use, and the lower the moisture content, the better. In a preferred embodiment of the present invention, in step S2, the molecular weight of the polyoxypropylene ether in the single-end allyl polyoxypropylene ether (APPG-OH) is 400 to 4000 (abbreviated as APPG-400-OH to APPG-4000-OH, and the molecular weight of the entire single-end allyl polyoxypropylene ether is 400+41 to 4000+41). For example, in step S2, a single-end allyl polyoxypropylene ether (APPG-400-OH) with a molecular weight of 400 can be used, and a single-end allyl polyoxypropylene ether with a molecular weight of 1000 can also be used. The single-end allyl polyoxypropylene ether (APPG-1000-OH) can be used, and the single-end allyl polyoxypropylene ether (APPG-2000-OH) with a molecular weight of 2000 can also be used, and the single-end allyl polyoxypropylene ether (APPG-2500-OH) with a molecular weight of 2500 can also be used. The single-end allyl polyoxypropylene ether (APPG-3000-OH) with a molecular weight of 3000 can also be used, and the single-end allyl polyoxypropylene ether (APPG-4000-OH) with a molecular weight of 4000 can also be used. In step S2, the single-end allyl polyoxypropylene ether (APPG-2000-OH) with a molecular weight of 2000 is more preferably used.

[0016] In a preferred embodiment of the present invention, in step S2, the molar ratio of the single-end allyl polyoxypropylene ether to aminoalkylsilane is (0.9-1.05): 1. In the present invention, when the molar ratio of the single-end allyl polyoxypropylene ether to aminoalkylsilane is too large, the strength of the sealant will decrease.

[0017] In a specific embodiment of the present invention, in step S2, the reflux temperature is 70-100°C. In the reaction, dealcoholization is carried out while reacting at the reflux temperature (usually by atmospheric distillation). When no obvious fraction is produced, it also indicates the end of the reaction.

[0018] In a specific embodiment of the present invention, in order to further improve the performance of the obtained carbamate silane-terminated polyether, in step S2, after removing the unreacted alcohol and amino acid ester silane, it is necessary to cool down to room temperature under nitrogen protection. The applicant unexpectedly found that if the cooling step is carried out in the air or nitrogen is not continuously introduced during the cooling step, the performance of the obtained product will be greatly reduced.

[0019] In a preferred embodiment of the present invention, in step S3, the double-terminal hydrogen-containing silane compound is a hydrogen-containing double-headed or terminal hydrogen-containing silicone oil, preferably terminal hydrogen-containing silicone oil, and further preferably terminal hydrogen-containing silicone oil with a hydrogen content of 0.04-0.12%. In a preferred embodiment of the present invention, for example, terminal hydrogen-containing silicone oil with a hydrogen content of 0.04-0.05%, terminal hydrogen-containing silicone oil with a hydrogen content of 0.06-0.08%, and terminal hydrogen-containing silicone oil with a hydrogen content of 0.10-0.12% can be used, and terminal hydrogen-containing silicone oil with a hydrogen content of 0.10-0.12% is more preferred.

[0020] In a preferred embodiment of the present invention, in step S3, the molar ratio of the double-terminal hydrogen-containing silane compound to the aminohydrocarbon silane is (0.4-0.5):1.

[0021] In a preferred embodiment of the present invention, in step S3, the amount of the second catalyst is such that the Pt content in the system is 20 to 50 ppm. In a preferred embodiment of the present invention, the preparation method of the second catalyst comprises the following steps:

[0022] Under nitrogen protection, chloroplatinic acid hexahydrate and a vinylsilane compound are mixed in an organic solvent, reacted at 60-80° C. for 0.5-1 h, and the solid is removed by filtration to obtain the product.

[0023] In a preferred embodiment of the present invention, in order to further improve the performance of the obtained sealant, the vinylsilane compound in the preparation method of the second catalyst is tetramethyltetravinylcyclotetrasiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane or 1,3-divinyl-1,1,3,3-tetramethyldisilazane or 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasilazane, and more preferably 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasilazane. Wherein, in the preparation method of the second catalyst, the molar ratio of platinum to vinylsilane in chloroplatinic acid hexahydrate is preferably 1: (2 to 4).

[0024] In a preferred embodiment of the present invention, the organic solvent in the preparation method of the second catalyst is isopropanol and / or toluene, and more preferably isopropanol and toluene in a volume ratio of (1 to 2): 1. The amount of the organic solvent used is a commonly used amount of solvent in the art, for example, 6 to 10 mL / g of the total amount of the raw material.

[0025] In a specific embodiment of the present invention, in the preparation method of the second catalyst, usually under nitrogen protection, after chloroplatinic acid hexahydrate is mixed with an organic solvent, a vinyl silane compound is added to achieve mixing of chloroplatinic acid hexahydrate with the vinyl silane compound in an organic solvent. In the actual operation process of the present invention, in order to reduce the impact of water on the reaction, chloroplatinic acid hexahydrate is usually mixed with an organic solvent before adding the vinyl silane compound to remove water. Conventional methods in the art can be used to remove water, such as by adding anhydrous magnesium sulfate to remove water, etc.

[0026] In a specific embodiment of the present invention, in the preparation method of the second catalyst, if 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasilazane is used as the vinylsilane compound to prepare the second catalyst, no dechlorination is required after the reaction. If other vinylsilane compounds are used to prepare the second catalyst, a dechlorination step may also be included after the reaction. Dechlorination may be performed using conventional methods in the art, such as dechlorination by adding sodium bicarbonate.

[0027] In a preferred embodiment of the present invention, in step S3, the double-terminal hydrogen-containing silane compound and the second catalyst can be first activated at 70-80°C for 10-20 minutes, and then the product obtained in step S2 is added and mixed, and then reacted at 75-90°C for 2-3 hours.

[0028] In the prior art, modified polyethers are used to prepare sealants, but the sealants cannot have both good tensile properties and deep curing properties, and can only be improved by adding additives with corresponding functions. However, adding corresponding functional additives to the sealants will introduce new problems. The modified polyethers obtained by the preparation method provided by the present invention are used to prepare sealants, and the obtained sealants can have both good tensile properties and deep curing properties without adding corresponding functional additives. If in actual applications, the sealant needs to have both excellent tensile properties and deep curing properties, the modified polyethers provided by the present invention can be used to prepare the sealants, and the use of additives with related functions can be greatly reduced compared with the prior art.

[0029] Another object of the present invention is to provide a modified polyether obtained by the above preparation method.

[0030] Another object of the present invention is to provide the use of the above preparation method or the modified polyether obtained by the above preparation method in the preparation of building sealants.

[0031] The beneficial effects of the present invention are:

[0032] The modified polyether obtained by the preparation method provided by the present invention is used to prepare a sealant, so that the obtained sealant can have both good tensile properties and deep curing properties, thereby improving the situation in the prior art where the polyether used to prepare the sealant cannot make the sealant have both good tensile properties and deep curing properties and can only be achieved by adding other additives. DETAILED DESCRIPTION

[0033] The following examples are used to further describe the specific embodiments of the present invention. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. In the present invention, unless otherwise specified, "%" is a mass percentage. In the specific embodiments of the present invention, the hydrogen-containing silicone oil was purchased from Ningbo Runhe Materials.

[0034] Example 1

[0035] This embodiment provides a modified polyether, and the preparation method comprises the following steps:

[0036] S1, under nitrogen protection, 180.2g of dimethyl carbonate with a water content of 182ppm and 179.3g of γ-aminopropyltrimethoxysilane were heated in 1.2g of a methanol solution containing 29-29.5% sodium methoxide until obvious reflux occurred at about 76°C, and the reaction was kept warm for 2h. The content of aminopropyltrimethoxysilane was 0.21% under gas phase monitoring. The mixture was cooled and neutralized with glacial acetic acid to a pH of about 6.4. Methanol was recovered by heating at 100-110°C under normal pressure, cooled to 72-75°C, and excess dimethyl carbonate was recovered at -0.04-0.05MPa. The mixture was heated to 142-145°C, and the fractions were collected by distillation at -0.07-0.08MPa to obtain colorless and transparent methyl carbamate propyltrimethoxysilane.

[0037] S2, under nitrogen protection, heat 2041g of APPG-2000-OH with a moisture content of 320ppm and the obtained methyl carbamate propyl trimethoxysilane at 82-85°C to react until reflux occurs, and carry out dealcoholization by atmospheric distillation at the reflux temperature until no obvious fraction is produced, slowly heat to 142-145°C, and remove unreacted methyl carbamate propyl trimethoxysilane under reduced pressure of -0.07-0.08MPa, and cool under nitrogen protection to obtain the product.

[0038] S3: Under nitrogen protection, 833g of double-ended hydrogenated silicone oil with a hydrogen content of 0.1-0.12% and the second catalyst (the amount of the second catalyst is such that the Pt content in the system is 28ppm) are activated at 80°C for 10min, S2 product is added to maintain the temperature at 78-81°C for 3h, dried activated carbon is added to treat for 0.5h, hot filtration is performed, and the filtrate is obtained.

[0039] The preparation method of the second catalyst in Example 1 comprises the following steps:

[0040] Under nitrogen protection, 1 g of chloroplatinic acid hexahydrate was dissolved in 20 ml of a mixed solution of isopropanol and toluene in a volume ratio of 1:1, 1.6 g of anhydrous magnesium sulfate and 2 g of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasilazane silane were added, and the mixture was reacted at 82-85°C for 1 h, and the temperature was raised to 115°C for further reaction for 1 h, and the temperature was lowered and the solid was filtered to remove the solid to obtain a dark green transparent liquid.

[0041] Example 2

[0042] The method provided in this embodiment is the same as that in Embodiment 1, the only difference is that 0.5 mol of hydrogen-containing silicone oil having a hydrogen content of 0.06-0.08% is used in step S3.

[0043] Example 3

[0044] The method provided in this embodiment is the same as that in Embodiment 1, the only difference being that in step S2, 1 mol of polyoxypropylene ether with a water content of 262 ppm and a molecular weight of 1000 (APPG-1000-OH) is used.

[0045] Example 4

[0046] The method provided in this embodiment is the same as that in Example 1, except that in step S2, 1 mol of single-end allyl polyoxypropylene ether (APPG-4000-OH) with a moisture content of 321 ppm and a molecular weight of 4000 is used, and in step S3, 0.5 mol of hydrogenated silicone oil with a hydrogen content of 0.06 to 0.08% is used.

[0047] Example 5

[0048] The method provided in this embodiment is the same as that in Example 1, except that in step S2, 1 mol of single-end allyl polyoxypropylene ether (APPG-400-OH) with a moisture content of 466 ppm and a molecular weight of 400 is used, and in step S3, 0.5 mol of hydrogenated silicone oil with a hydrogen content of 0.04 to 0.05% is used.

[0049] Example 6

[0050] This embodiment provides a modified polyether, and the preparation method comprises the following steps:

[0051] S1, under nitrogen protection, 225.2g of dimethyl carbonate with a water content of 182ppm and 179.3g of γ-aminopropyltrimethoxysilane were heated in 2.43g of a methanol solution containing 29-29.5% sodium methoxide until obvious reflux occurred at about 76°C, and the reaction was kept warm for 2h. The content of aminopropyltrimethoxysilane was 0.08% under gas phase monitoring. The mixture was cooled and neutralized with glacial acetic acid to a pH of about 6.4. Methanol was recovered by heating at 100-110°C under normal pressure, cooled to 72-75°C, and excess dimethyl carbonate was recovered at -0.04-0.05MPa. The mixture was heated to 142-145°C, and the fractions were collected by distillation at -0.07-0.08MPa to obtain colorless and transparent methyl carbamate propyltrimethoxysilane.

[0052] S2, under nitrogen protection, heat 2215.4g of APPG-2000-OH with a moisture content of 320ppm and the obtained methyl carbamate propyl trimethoxysilane at 82-85°C to react until reflux occurs, and carry out dealcoholization by atmospheric distillation at the reflux temperature until no obvious fraction is produced, slowly heat to 142-145°C, and remove unreacted methyl carbamate propyl trimethoxysilane under reduced pressure of -0.07-0.08MPa, and cool under nitrogen protection to obtain the product.

[0053] S3: Under nitrogen protection, 1000.2g of double-ended hydrogenated silicone oil with a hydrogen content of 0.1-0.12% and a second catalyst (the second catalyst is the second catalyst provided in Example 1, and the amount of the second catalyst is such that the Pt content in the system is 55ppm) are activated at 80°C for 20min, S2 product is added and the temperature is maintained at 78-81°C for 3h, dried activated carbon is added and treated for 0.5h and hot filtered to obtain the product.

[0054] Example 7

[0055] The method provided in this embodiment is the same as that in Embodiment 1, except that the carbonate used in step S1 is ethyl carbonate and the aminoalkylsilane is aminopropyltriethoxysilane.

[0056] Example 8

[0057] The method provided in this embodiment is the same as that in Embodiment 1, except that the preparation method of the second catalyst in step S3 is different. The preparation method of the second catalyst in step S3 of this embodiment includes the following steps:

[0058] Under nitrogen protection, dissolve 1 g of chloroplatinic acid hexahydrate in 20 ml of a mixed solution of isopropanol and toluene in a volume ratio of 1:1, add 1.6 g of anhydrous magnesium sulfate, add 2 g of tetramethyltetravinylcyclotetrasiloxane silane, react at 82-85 ° C for 1 h, heat to 115 ° C and continue to react for 1 h, cool to about 50 ° C, add 1.2 g of sodium bicarbonate and continue stirring for 0.5 h, cool, filter to remove solids, and obtain a dark green transparent liquid.

[0059] Example 9

[0060] The method provided in this embodiment is the same as that in Embodiment 1, except that the aminohydrocarbon silane used in step S1 is N-β-aminoethyl-γ-aminopropyltrimethoxysilane.

[0061] Example 10

[0062] The method provided in this embodiment is the same as that in Embodiment 1, except that the aminosilane used in step S1 is γ-n-butylaminopropyltrimethoxysilane.

[0063] Comparative Example 1

[0064] CN202111280918.2 Silane-modified polyether prepared in Example 6.

[0065] Comparative Example 2

[0066] Under nitrogen protection, 41g of isocyanatepropyltrimethoxysilane and 300g of polypropylene glycol PPG-6000 were mixed evenly at room temperature, 0.3% by mass of methanol solution containing 29-29.5% sodium methoxide was added to the mixed raw materials, and the mixture was reacted at 80°C for 2h. Low-boiling substances were removed at 150°C -0.04 to -0.05MPa for 0.5h until no obvious bubbles were found.

[0067] Experimental example

[0068] The products obtained in the examples and comparative examples of the present invention were used to prepare sealants for performance testing.

[0069] The preparation method of the sealant is as follows: 100 parts by mass of the modified polyether provided in the embodiment and the comparative example, 80 parts by mass of polypropylene glycol-6000, 160 parts by mass of active light calcium carbonate, 40 parts by mass of heavy calcium carbonate, 60 parts by mass of carbon black (all fillers are -0.05 to -0.06 MPa, 85°C drying treatment for more than 12 hours), 20 parts of diisodecyl phthalate, and 1 part by mass of polysilicate methyl ester Si56 are mixed and stirred evenly, and heated at 120°C, -0.1 to -0.12 MPa to remove After the mixture is cooled to low, 1.5 parts by mass of 2,6-butyl-4-methylphenol are added thereto, and the mixture is stirred at 1000 r / min in a planetary stirrer for 15 min until it is evenly dispersed. Then 1 part by mass of bis-[3-(trimethoxysilyl)-propyl]amine and 1 part by mass of γ-(2,3-epoxypropoxy)propyltrimethoxysilane are added and stirred evenly. Finally, 1 part by mass of tin octoate is added, and the mixture is mixed at -0.09 to -0.1 MPa for 15 min. The mixture is cooled under nitrogen protection to obtain a sealant.

[0070] Among them, the surface drying time and 6h curing depth were tested according to GB / T 13477.5-2002, and the tensile strength and elongation at break were tested according to GB / T528-2009. The results are shown in Table 1 below.

[0071] Table 1 Sealant performance results

[0072]

[0073]

[0074] As can be seen from Table 1, compared with the sealant prepared using the modified polyether provided in the comparative example (tensile strength of 2.7 MPa, 6h curing depth of 4.6 mm), the tensile strength and deep curing performance of the sealant prepared using the modified polyether provided by the present invention can be effectively improved (tensile strength of at least 3.0 MPa, 6h curing depth of at least 5.0 mm), so that the obtained sealant can have both good tensile properties and deep curing performance.

[0075] Finally, the method of the present invention is only a preferred embodiment and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a modified polyether, characterized in that: The steps include: S1, under nitrogen protection, carbonate, aminosilane and a first catalyst are mixed, reacted under reflux until the content of aminosilane in the system is ≤0.3%, after the reaction is completed, the pH value of the system is adjusted to 6-7, and the carbamate silane is collected at 140-160° C. and -0.07--0.08 MPa; the first catalyst is an alkali metal, a transition metal, an alkali metal oxide or a saturated alcohol solution of an alkali metal; S2, under nitrogen protection, mixing the carbamate silane obtained in step S1 with the single-end allyl polyoxypropylene ether, distilling and dealcoholizing under reflux until no obvious fraction is produced, removing unreacted carbamate silane, and cooling the temperature to room temperature under nitrogen protection to obtain a product; S3, under nitrogen protection, mixing the product obtained in step S2, the double-terminal hydrogen-containing silane compound and the second catalyst, reacting at 75-90° C. for 2-3 hours, adding activated carbon for treatment for 0.5-1 hour after the reaction, and filtering hot to obtain the product; the second catalyst is vinyl silane platinum.

2. The preparation method according to claim 1, characterized in that: In step S3, the double-terminal hydrogen-containing silane compound is a hydrogen-containing double-capped or terminal hydrogen-containing silicone oil, preferably a terminal hydrogen-containing silicone oil, and more preferably a terminal hydrogen-containing silicone oil with a hydrogen content of 0.10-0.12%.

3. The preparation method according to claim 1 or 2, characterized in that: In step S3, the molar ratio of the double-terminal hydrogen-containing silane compound to the aminohydrocarbon silane is (0.4-0.5):

1.

4. The preparation method according to any one of claims 1 to 3, characterized in that In step S3, the second catalyst is used in an amount such that the Pt content in the system is 20 to 50 ppm.

5. The preparation method according to any one of claims 1 to 3, characterized in that: In step S3, the preparation method of the second catalyst comprises the following steps: Under nitrogen protection, chloroplatinic acid hexahydrate and a vinylsilane compound are mixed in an organic solvent, reacted at 60-80° C. for 0.5-1 h, impurities are removed, and solids are filtered out to obtain the product.

6. The preparation method according to any one of claims 1 to 3, characterized in that: In step S2, the molecular weight of the polyoxypropylene ether in the single-end allyl polyoxypropylene ether is 400-4000, preferably 2000.

7. The preparation method according to any one of claims 1 to 3, characterized in that In step S2, the molar ratio of the single-end allyl polyoxypropylene ether to the aminoalkylsilane is (0.9-1.05):

1.

8. The preparation method according to any one of claims 1 to 3, characterized in that: In step S1, the carbonate is dimethyl carbonate, diethyl carbonate or dipropyl carbonate, preferably dimethyl carbonate; And / or, the aminoalkylsilane is γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-n-butylaminopropyltrimethoxysilane or piperazinylpropyltrimethoxysilane, preferably γ-aminopropyltrimethoxysilane.

9. The modified polyether prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the preparation method according to any one of claims 1 to 8 or the modified polyether according to claim 9 in the preparation of building sealants.

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