A modified polyether and a method for preparing and using the same

Abstract

The application provides a modified polyether and a preparation method and application thereof. The preparation method of the modified polyether comprises the following steps: S1, mixing a carbonate, an amino hydroxyl group silane and a first catalyst under nitrogen protection, adjusting the pH value to neutral after reaction, and collecting the carbamate group silane; S2, mixing the product of S1 with a single end allyl polyoxypropylene ether under nitrogen protection, removing unreacted alcohol and amino acid ester silane after reaction, and obtaining the product by reducing to room temperature under nitrogen protection; S3, mixing the product obtained in S2, a double end hydrogen-containing silane compound and a second catalyst under nitrogen protection, reacting at 75-90 DEG C for 2-3 h, adding activated carbon, and obtaining the product after hot filtration; the second catalyst is a vinyl silane platinum compound. The modified polyether provided by the application can make the sealant have good tensile property and deep curing property.

Description

Technical Field

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

[0002] Due to its excellent performance, sealants are widely used in various applications, such as filling gaps, waterproofing, heat insulation, earthquake resistance, etc. Sealants include polysulfide sealants, silicone sealants, polyurethane sealants, silane-modified sealants, etc. Silane-modified sealants were originally elastic sealants based on end-capped alkyl polyethers. Later, due to its special properties, it quickly gained favor among researchers in various countries. To date, researchers have called single-component or two-component elastic sealants 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 many 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. To address this problem, the R&D team provided a preparation method with a specific sequence and used a specific chain extender such as a double-terminal hydrogen-containing silane compound, which effectively improved 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 problems of high activity and easy disproportionation of trimethoxyhydrogen-containing silane, easy deactivation of the catalyst, dark color of the obtained silane-modified polyether product, incomplete silane end-capping modification, and poor moisture depth curing of the sealant. 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, mixing a carbonate, aminosilane, and a first catalyst, reacting under reflux until the aminosilane content in the system is ≤0.3%, adjusting the pH of the system to 6-7 after the reaction, and collecting the carbamate silane 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, and 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 the product;

[0008] S3, under nitrogen protection, mixing the product obtained in step S2, a double-terminal hydrogen-containing silane compound and a second catalyst, reacting at 75-90°C for 2-3 hours. After the reaction, adding activated carbon for treatment for 0.5-1 hour, and hot filtering to obtain the product; the second catalyst is vinylsilane 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 carbonates easily 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 to below 500ppm before use.

[0010] In a preferred embodiment of the present invention, 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). Applicants have discovered that when γ-aminopropyltrimethoxysilane is selected as the aminoalkylsilane and reacted with other ingredients under a specific preparation method, the resulting sealant has optimal performance.

[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, transition metal, alkali metal oxide, or saturated alcohol solution of an alkali metal. Preferably, it is a saturated alcohol solution of an alkali metal, and more preferably, a saturated sodium methoxide / methanol solution. In specific embodiments of the present invention, the concentration of the saturated alcohol solution of the alkali metal is 10-30%. In preferred embodiments, the concentration of the saturated sodium methoxide / methanol solution can be 29-29.5%. In specific embodiments of the present invention, the amount of the first catalyst used in step S1 is preferably 0.2%-0.5% of the total mass of the carbonate and aminosilane (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 of the system is typically adjusted to 6-7 after the system temperature drops to room temperature. Preferably, a neutralizer is used to adjust the pH of the system to 6-7. The neutralizer is preferably an organic acid such as acetic acid or oxalic acid, or other inorganic acid that can adjust the pH to 6-7 without causing hydrolysis between the silane and the product, with acetic acid being more preferred.

[0014] In a preferred embodiment of the present invention, in step S1, after the pH value of the system is adjusted to 6-7, atmospheric distillation can be performed at 100-130° C. until no fraction is produced, and then the temperature is lowered to 70-90° C. and the unreacted carbonate is recovered at -0.04-0.06 MPa, and then the carbamate silane is collected at 140-160° C. and -0.07-0.08 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 400~4000 (abbreviated as APPG-400-OH~APPG-4000-OH, and the molecular weight of the entire single-end allyl polyoxypropylene ether is 400+41~4000+41). For example, in step S2, a single-end allyl polyoxypropylene ether (APPG-400-OH) with a molecular weight of 400 can be used, or a single-end allyl polyoxypropylene ether with a molecular weight of 1000 can be used. Alternatively, propylene glycol ether (APPG-1000-OH) may be used. Alternatively, single-end allyl propylene glycol ether (APPG-2000-OH) having a molecular weight of 2000 may be used. Alternatively, single-end allyl propylene glycol ether (APPG-2500-OH) having a molecular weight of 2500 may be used. Alternatively, single-end allyl propylene glycol ether (APPG-3000-OH) having a molecular weight of 3000 may be used. Alternatively, single-end allyl propylene glycol ether (APPG-4000-OH) having a molecular weight of 4000 may be used. In step S2, single-end allyl propylene glycol ether (APPG-2000-OH) having a molecular weight of 2000 may be used.

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

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

[0018] In a specific embodiment of the present invention, to further improve the performance of the resulting carbamate silane-terminated polyether, in step S2, after removing unreacted alcohol and amino acid ester silane, the temperature is cooled to room temperature under nitrogen. The applicant unexpectedly discovered that if the cooling step is performed in air or if nitrogen is not continuously introduced during the cooling step, the performance of the resulting product is significantly reduced.

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

[0020] In a preferred embodiment of the present application, in step S3, the molar ratio of the di-terminated hydrogen-containing silane compound to the aminoalkylsilane is (0.4-0.5):1.

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

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

[0023] In a preferred embodiment of the present application, in order to further improve the performance of the sealant, in the preparation method of the second catalyst, the vinylsilane compound 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-tetra-vinylcyclotetrasilazane, and further preferably 1,3,5,7-tetramethyl-1,3,5,7-tetra-vinylcyclotetrasilazane. In the preparation method of the second catalyst, the molar ratio of platinum in the chloroplatinic acid hexahydrate to the vinylsilane is preferably 1:(2-4).

[0024] In a preferred embodiment of the present application, in the preparation method of the second catalyst, the organic solvent is isopropyl alcohol and / or toluene, and further preferably isopropyl alcohol and toluene in a volume ratio of (1-2):1. The amount of the organic solvent is the amount of the solvents commonly used in the art, such as 6-10 mL / g of the total amount of raw materials.

[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, vinylsilane compound is added to realize mixing chloroplatinic acid hexahydrate with vinylsilane 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, usually chloroplatinic acid hexahydrate is mixed with an organic solvent and then dewatered before adding vinylsilane compound. Conventional method dewatering can be used in this area, such as by adding anhydrous magnesium sulfate dewatering 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 chlorination step is required after the reaction. If other vinylsilane compounds are used to prepare the second catalyst, a chlorination step may also be included after the reaction. Chlorination can be removed using conventional methods in the art, such as by adding sodium bicarbonate.

[0027] In a preferred embodiment of the present invention, in step S3, the double-ended hydrogen-containing silane compound and the second catalyst can be 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] The prior art uses modified polyethers to prepare sealants, but these sealants cannot simultaneously achieve good tensile properties and deep curing performance. These properties can only be improved by adding additives with corresponding functional properties. However, adding these additives to the sealant introduces new problems. The modified polyethers obtained by the preparation method provided by the present invention are used to prepare sealants, and without the addition of these additives, the resulting sealant can achieve both good tensile properties and deep curing performance. If, in practical applications, a sealant requires both excellent tensile properties and deep curing performance, using the modified polyethers provided by the present invention can significantly reduce the use of additives with these functional properties compared to 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 construction sealants.

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

[0032] The modified polyether obtained by the preparation method provided by the application can be used to prepare sealant, which has good tensile property and deep curing property, so as to improve the situation that the polyether used for preparing sealant in the prior art cannot have good tensile property and deep curing property at the same time and can only be improved by adding other additives. DETAILED DESCRIPTION

[0033] The specific embodiments of the application are described in further detail below in conjunction with examples. The following examples are used to illustrate the application, but are not used to limit the scope of the application. In the application, "%" is mass percentage. In the specific embodiments of the application, the hydrogen-containing silicone oil is purchased from Ningbo Runhe Material.

[0034] Example 1

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

[0036] S1, under the protection of nitrogen, 180.2g of dimethyl carbonate with a water content of 182ppm is reacted with 179.3g of γ-aminopropyltrimethoxysilane in 1.2g of methanol solution containing 29-29.5% sodium methoxide, heated to about 76℃ until obvious reflux occurs, and kept at 76℃ for 2h. The content of aminopropyltrimethoxysilane is monitored by gas phase, and the pH is neutralized to about 6.4 by adding glacial acetic acid. The methanol is recovered at normal pressure and at 100-110℃, the temperature is lowered to 72-75℃, the excess dimethyl carbonate is recovered at-0.04~-0.05MPa, and the temperature is raised to 142-145℃. The aminomethylcarbamate propyltrimethoxysilane is collected by distillation at-0.07~-0.08MPa.

[0037] S2, under the protection of nitrogen, 2041g of APPG-2000-OH with a water content of 320ppm is reacted with the obtained aminomethylcarbamate propyltrimethoxysilane at 82-85℃ until reflux occurs. The alcohol is removed by distillation at normal pressure at the reflux temperature until no obvious fraction is produced. The temperature is slowly raised to 142-145℃, and the unreacted aminomethylcarbamate propyltrimethoxysilane is removed by vacuum distillation at-0.07~-0.08MPa. The product is obtained by lowering the temperature under the protection of nitrogen.

[0038] S3: Under the protection of nitrogen, 833g of double-end hydrogen-containing silicone oil with a hydrogen content of 0.1-0.12% is activated with the second catalyst (the amount of the second catalyst is determined according to the Pt content of 28ppm in the system) at 80℃ for 10min. The product of S2 is added to maintain the temperature at 78-81℃ for 3h. The activated carbon is added after drying to treat for 0.5h, and then filtered to obtain the filtrate.

[0039] The preparation method of the second catalyst in Example 1 includes 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. The mixture was reacted at 82-85°C for 1 h, then the temperature was raised to 115°C and the reaction was continued for 1 h. The temperature was lowered and the solid was removed by filtration to obtain a dark green transparent liquid.

[0041] Example 2

[0042] The method provided in this embodiment is the same as that in Example 1, except that 0.5 mol of hydrogenated 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 Example 1, except 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 0.06-0.08% 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 molecular weight of 400 and a water content of 466 ppm is used, and in step S3, 0.5 mol of hydrogenated silicone oil with a hydrogen content of 0.04-0.05% is used.

[0049] Example 6

[0050] This embodiment provides a modified polyether, and the preparation method includes 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. The reaction was kept warm for 2h. The aminopropyltrimethoxysilane content was 0.08% by gas phase monitoring. The mixture was cooled and neutralized by adding glacial acetic acid to a pH of about 6.4. The methanol was recovered by heating at 100-110°C under normal pressure. The temperature was lowered to 72-75°C and the excess dimethyl carbonate was recovered at -0.04-0.05MPa. The temperature was raised to 142-145°C and the fraction was collected by distillation at -0.07-0.08MPa to obtain colorless and transparent methyl carbamate propyltrimethoxysilane.

[0052] S2. Under nitrogen protection, 2215.4 g of APPG-2000-OH with a moisture content of 320 ppm and the obtained methyl carbamate propyl trimethoxysilane were heated to 82-85°C to react until reflux occurred. The alcohol was dealcoholized by atmospheric distillation at the reflux temperature until no obvious distillate was produced. The temperature was slowly raised to 142-145°C, and the unreacted methyl carbamate propyl trimethoxysilane was removed under reduced pressure of -0.07-0.08 MPa. The temperature was then lowered 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 the 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) were activated at 80°C for 20min, S2 product was added and the temperature was maintained at 78-81°C for 3h, dried activated carbon was 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 Example 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 Example 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 the protection of nitrogen, 1 g of chloroplatinic acid hexahydrate was dissolved in 20 ml of a mixed solution of isopropyl alcohol and toluene in a volume ratio of 1:1, 1.6 g of anhydrous magnesium sulfate was added, 2 g of tetramethyltetraethenylcyclotetrasiloxane silane was added, and the reaction was carried out at 82-85°C for 1 h, then the temperature was raised to 115°C and the reaction was continued for 1 h, then the temperature was lowered to about 50°C, 1.2 g of sodium bicarbonate was added, and the stirring was continued for 0.5 h, then the temperature was lowered, the solid was removed by filtration, and a dark green transparent liquid was obtained.

[0059] Example 9

[0060] The method provided in this example is the same as that in Example 1, except that the aminoalkylsilane used in step S1 is N-β-aminoethyl-γ-aminopropyltrimethoxysilane.

[0061] Example 10

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

[0063] Comparative Example 1

[0064] The silane-modified polyether prepared in Example 6 of CN202111280918.2.

[0065] Comparative Example 2

[0066] Under the protection of nitrogen, 41 g of isocyanate propyl trimethoxysilane was uniformly mixed with 300 g of polypropylene glycol PPG-6000 at room temperature, 0.3% of the mixed raw material by mass was added to a methanol solution containing 29-29.5% sodium methoxide, and the reaction was carried out at 80°C for 2 h, then the low boiling point was removed at 150°C-0.04~-0.05 MPa for 0.5 h until no obvious bubbles were generated.

[0067] Experimental Example 1

[0068] The products obtained in the examples and comparative examples of the present application 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~-0.06MPa, dried at 85℃ for more than 12h), 20 parts of diisodecyl phthalate, and 1 part by mass of polymethyl silicate Si56 are mixed and stirred evenly, and heated at 120℃, -0.1~-0.12MPa to remove After the mixture is cooled, 1 part by mass and 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 minutes until it is uniformly 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 minutes. The mixture is cooled under nitrogen protection to obtain a sealant.

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

[0071] Table 1 Sealant performance results

[0072] ;

[0073] 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, 6-hour 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, 6-hour curing depth of at least 5.0 mm), so that the obtained sealant can simultaneously achieve good tensile properties and deep curing performance.

[0074] Finally, the method of the present invention is only a preferred embodiment and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a modified polyether, characterized in that: The steps include: S1, under nitrogen protection, mixing a carbonate, aminosilane, and a first catalyst, reacting under reflux until the aminosilane content in the system is ≤0.3%, adjusting the pH value of the system to 6-7 after the reaction, and collecting the carbamate silane 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; the carbonate is dimethyl carbonate, diethyl carbonate, or dipropyl carbonate; 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, a double-ended hydrogen-containing silane compound and a second catalyst, reacting at 75-90° C. for 2-3 hours, adding activated carbon for treatment for 0.5-1 hour, and hot filtering to obtain the product; the second catalyst is vinyl silane platinum; the double-ended hydrogen-containing silane compound is a hydrogen-containing double-end or double-ended hydrogen-containing silicone oil.

2. The preparation method according to claim 1, characterized in that In step S3, the double-terminal hydrogen-containing silane compound is a double-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 claim 1 or 2, characterized in that In step S3, the amount of the second catalyst used is such that the Pt content in the system is 20-50 ppm.

5. The preparation method according to claim 1 or 2, 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 0.5-1h, impurities are removed, and solids are filtered out to obtain the product.

6. The preparation method according to claim 1 or 2, characterized in that In step S2, the molecular weight of the polyoxypropylene ether in the single-end allyl polyoxypropylene ether is 400-4000.

7. The preparation method according to claim 6, characterized in that In step S2, the molecular weight of the polyoxypropylene ether in the single-end allyl polyoxypropylene ether is 2000.

8. The preparation method according to claim 1 or 2, characterized in that In step S2, the molar ratio of the single-ended allyl polyoxypropylene ether to the aminoalkylsilane is (0.9-1.05):

1.

9. The preparation method according to claim 1 or 2, characterized in that: In step S1, the carbonate is 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.

10. The preparation method according to claim 1 or 2, characterized in that: In step S1, the aminohydrocarbon silane is γ-aminopropyltrimethoxysilane.

11. The modified polyether prepared by the preparation method according to any one of claims 1 to 10.

12. Use of the modified polyether according to claim 11 in preparing a building sealant.