Silane-terminated polyether and preparation method thereof

Abstract

The invention discloses silane-terminated polyether and a preparation method thereof, and belongs to the technical field of silane-terminated polyether. According to the preparation method disclosed by the invention, more stable chlorosilane is creatively used for replacing extremely unstable alkoxy silane as a preparation raw material of the silane-terminated polyether, so that great convenience is brought to storage and use of the raw material in production; the hydrogen-terminated silicone oil and the polyether with lower molecular weight react to directly obtain the diallyl-terminated high-molecular-weight polyether, so that difficult synthesis of the high-molecular-weight polyether and a complex desalting process are avoided; the product obtained by the invention does not contain unstable nitrogen-containing groups, and a polysiloxane chain segment with better stability is introduced, so that the terminal sealant product can be endowed with better aging resistance and weather resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of silane - terminated polyethers, and specifically relates to a silane - terminated polyether and a preparation method thereof. Background Art

[0002] Silane - terminated polyethers, also known as organosilicon - modified polyethers, were first developed by Kaneka Chemical of Japan for use in sealants. Its main structure is to graft hydrolyzable siloxane groups at the ends of polyether (usually polypropylene glycol) chains. Its molecular structure is as follows:

[0003]

[0004] Its main chain structure is similar to that of polyether - type polyurethane prepolymers, while the end groups are similar to those of silicone polymers. Therefore, it combines the advantages of both polymers, and the sealants made from it have excellent comprehensive properties.

[0005] One method for preparing silane - terminated polyethers is through the capping reaction of a siloxane compound containing an isocyanate group (-NCO) with a polyether containing terminal hydroxyl groups. The products prepared by this method contain urethane groups, which can deteriorate the anti - aging and weather resistance of the products, and also cause the products to self - cure before use, resulting in a short shelf life. The silane - terminated polyethers of Wacker Chemical adopt this structure, and Patent CN105085863B also reports a similar structure and synthesis method.

[0006] Another method for preparing silane - terminated polyethers is the double - bond hydrosilylation method, which directly adds a hydrolyzable silane to a polyether with a double bond at the end, avoiding the introduction of nitrogen - containing groups and improving the stability of the polymer. The silane - terminated polyethers sold by Kaneka Chemical and AGC Asahi Glass adopt the above - mentioned structure. However, the silanes used in this method, such as methyldimethoxysilane (CH 3 O) 2 SiHCH 3 and trimethoxysilane (CH 3 O) 3 SiH, are molecules with extremely high activity and instability, and have a very short shelf life, causing many inconveniences in the storage and use of raw materials.

[0007] The main raw material for preparing silane - terminated polyethers by the double - bond hydrosilylation method is a high - molecular - weight polyether with terminal double bonds (usually polypropylene glycol). However, it is difficult to directly synthesize high - molecular - weight polyethers, and they are usually obtained by chain extension of low - molecular - weight polyethers. Dichloromethane or 1,2 - dichloroethane (such as in patent CN105001408A) is usually used as a chain extender, which reacts with pre - alkoxylated polyethers (reacting polyethers with alkali metal alkoxides or hydroxides) to obtain the product, and finally the by - product salts are removed. Although companies such as Mitsui Chemicals and Asahi Glass can directly synthesize high - molecular - weight polyethers, further double - bond capping at the terminal is still required. Generally, it is also through the reaction of alkoxylated polyethers with allyl chloride and finally desalting. No matter which method is used, desalting of high - molecular - weight polyethers is inevitable. In high - molecular - weight polyethers, salts will crystallize into very fine particles, which are difficult to filter out and even form complexes with polyethers. Patent CN111499858A discloses a method for refining crude viscous polymers, but this method uses saturated brine added to the crude polyether for stratification. For high - molecular - weight diallyl - terminated polypropylene glycol, the stratification effect is very poor and it is not suitable. The salts remaining in the double - bond - terminated high - molecular - weight polyethers will affect the subsequent addition reaction with silanes, resulting in the inability to synthesize silane - terminated polyethers finally. Summary of the Invention

[0008] In view of the disadvantages in the existing synthesis process of silane - terminated polyethers, such as poor stability of the raw material silane, difficulty in synthesizing double - bond - terminated high - molecular - weight polyethers or difficulty in desalting, the present invention provides a silane - terminated polyether and its preparation method, effectively avoiding these problems during the synthesis process, and the obtained product does not contain nitrogen - containing groups that will cause poor product stability.

[0009] A silane - terminated polyether, the silane - terminated polyether has a structure represented by the following general formula (I):

[0010]

[0011] Wherein: m is a number between 4 and 80;

[0012] n is a number between 5 and 80;

[0013] x is a number between 1 and 20;

[0014] R 1 is Me, Et, OMe or OEt;

[0015] R 2 is OMe or OEt;

[0016] The molecular weight of the whole molecule is 2000 - 20000.

[0017] A silane - terminated polyether and its preparation method, comprising the following steps:

[0018] Step (1): Under nitrogen conditions, allyl-terminated polypropylene glycol, amino-terminated poly(dimethylsiloxane), and a platinum catalyst are fully stirred and mixed, and continuously stirred and reacted at 60-90 °C for 4-8 h to obtain an allyl-terminated propylene glycol-dimethylsiloxane copolymer. The reaction formula of step (1) is as follows:

[0019]

[0020] Step (2): A hydrosilane compound is added to the allyl-terminated propylene glycol-dimethylsiloxane copolymer obtained in step (1), and continuously stirred and reacted at 60-90 °C for 4-8 h, and then small molecule compounds in the reaction system are removed by vacuum. The reaction formula of step (2) is as follows:

[0021]

[0022] Step (3): Anhydrous methanol or ethanol is added to the reaction product obtained in step (2), and continuously stirred and reacted at 20-50 °C for 1-5 h, and then small molecule compounds in the reaction system are removed by vacuum to obtain a silane-terminated polyether. The reaction formula of step (3) is as follows:

[0023]

[0024] where R 3 is Me, Et or Cl, and other groups and degrees of polymerization are as described above;

[0025] The allyl-terminated polypropylene glycol has a structure represented by the following general formula (II):

[0026]

[0027] where m is a number between 4 and 80;

[0028] The amino-terminated poly(dimethylsiloxane) has a structure represented by the following general formula (III):

[0029]

[0030] where n is a number between 5 and 80;

[0031] The platinum catalyst is a Speier catalyst or a Karstedt catalyst, and its dosage is that the platinum dosage in the reaction system of step (1) is 5-20 ppm of the total amount of reaction raw materials;

[0032] The hydrosilane compound is methyl dichlorosilane, ethyl dichlorosilane or trichlorosilane, and its dosage is 2.1-8 times the molar amount of the allyl-terminated propylene glycol-dimethylsiloxane copolymer obtained in step (1).

[0033] A silane - terminated polyether and its preparation method. In the step (1), the molar ratio of diallyl - terminated polypropylene glycol to amino - terminated poly(dimethylsiloxane) is (x + 1):x, where x is a number between 1 and 20.

[0034] Preferably, in the step (1), an anhydrous solvent is added to dilute the whole reaction system, which is beneficial to the chain - extension in step (1) and the hydrosilylation in step (2). The reactive groups of diallyl - terminated polypropylene glycol, amino - terminated poly(dimethylsiloxane), and diallyl - terminated propylene glycol - dimethylsiloxane copolymer are all at the ends of the polymer chains and are easily wrapped by the polymer chains, making it difficult to collide with other groups and react. When the molecular weight is very large, the influence is particularly obvious. Adding a solvent for dilution is beneficial for the reactive groups at the chain ends to be more easily released to participate in the reaction, thus improving the reaction efficiency.

[0035] Preferably, the anhydrous solvent is selected from alkanes, cycloalkanes, aromatic hydrocarbons with 6 - 8 carbon atoms or their mixtures.

[0036] Preferably, the feeding ratio of the anhydrous solvent to the total weight of diallyl - terminated polypropylene glycol and amino - terminated poly(dimethylsiloxane) in the step (1) of the method of the present invention is (0.5 - 5):1.

[0037] Preferably, in the step (3), the amount of anhydrous methanol or ethanol used is 10 - 50 times the molar amount of the diallyl - terminated propylene glycol - dimethylsiloxane copolymer obtained in the step (1).

[0038] Those skilled in the art can understand that the degree of polymerization and molecular weight described in the present invention are only design values or theoretical average values, and do not represent that each molecule in the system actually has such a degree of polymerization or molecular weight, and there may be a certain gap between them and the measured values obtained by different testing methods.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] (1) The present invention innovatively uses a more stable chlorosilane instead of an extremely unstable alkoxysilane as the raw material for preparing silane - terminated polyether, bringing great convenience to the storage and use of raw materials in production;

[0041] (2) The present invention uses terminal - hydrogen silicone oil to react with a lower - molecular - weight polyether to directly obtain a high - molecular - weight polyether with diallyl end - groups, avoiding the difficult synthesis of high - molecular - weight polyether and the complex desalting process;

[0042] (3) The product obtained by the present invention not only does not contain unstable nitrogen - containing groups, but also introduces a more stable polysiloxane chain segment, which can endow the terminal sealant product with better anti - aging and weather resistance. Detailed implementation mode

[0043] The following examples describe in more detail the process of preparing silane - terminated polyethers according to the method of the present invention, and these examples are given by way of illustration, aiming to enable those skilled in the art to understand the content of the present invention and implement it accordingly, but these examples in no way limit the scope of the present invention.

[0044] The diallyl - terminated polypropylene glycol, amino - terminated poly(dimethylsiloxane), platinum catalyst, and other chemicals used in the comparative examples and examples of the present invention are all general reagent - grade or industrial - grade products, and are obtained by commercial purchase. The Speier catalyst used is an isopropanol solution of chloroplatinic acid (Pt mass fraction 2%), and the Karstedt catalyst is an xylene solution of 1,3 - divinyl - 1,1,3,3 - tetramethyldisiloxane platinum(0) (Pt mass fraction 2%).

[0045] In the examples, the weight - average molecular weight of the diallyl - terminated propylene glycol - dimethylsiloxane copolymer was determined by GPC, and the test conditions were as follows:

[0046] Instrument name: Waters 1515; Detector: Waters 2414 Refractive Index Detector, temperature 40°C; Column parameters: Styragel HR1 (molecular weight 100 - 500), Styragel HR2 (molecular weight 500 - 30000), Styragel HR4 (molecular weight 5000 - 600000) in series, temperature 40°C; Mobile phase: tetrahydrofuran (HPLC grade), flow rate 1 mL / minute; Standard: polyethylene glycol.

[0047] Example 1

[0048] A silane - terminated polyether, and its preparation steps are as follows:

[0049] (1) Under nitrogen conditions, 400 g of diallyl - terminated polypropylene glycol (molecular weight about 400, 1.0 mol), 720 g of amino - terminated poly(dimethylsiloxane) (molecular weight about 800, 0.9 mol), 0.6 kg of n - heptane, and 0.3 g of Speier catalyst were fully stirred and mixed, and continuously stirred and reacted at about 80°C for 6 h to obtain a diallyl - terminated propylene glycol - dimethylsiloxane copolymer, and the measured weight - average molecular weight was 11364;

[0050] (2) 46 g of methyldichlorosilane (0.4 mol) was added to the product obtained in step (1), and continuously stirred and reacted at about 80°C for 8 h, and then small - molecule compounds in the reaction system, including the solvent, were removed by vacuum.

[0051] (3) Add 38.4 g of anhydrous methanol (1.2 mol) to the product obtained in step (2), continuously stir and react at about 40 °C for 2 h, and then vacuum-remove the small-molecule compounds in the reaction system to obtain the product.

[0052] Example 2

[0053] A silane-capped polyether is prepared as follows:

[0054] (1) Under nitrogen conditions, add 1000 g of diallyl-capped polypropylene glycol (molecular weight about 1000, 1.0 mol), 250 g of amino-capped poly(dimethylsiloxane) (molecular weight about 500, 0.5 mol) and 1.0 g of Karstedt catalyst, stir and mix well, and continuously stir and react at about 70 °C for 4 h to obtain a diallyl-capped propylene glycol-dimethylsiloxane copolymer, and the measured weight-average molecular weight is 2587;

[0055] (2) Add 172.5 g of methyl dichlorosilane (1.5 mol) to the product obtained in step (1), continuously stir and react at about 90 °C for 4 h, and then vacuum-remove the small-molecule compounds in the reaction system;

[0056] (3) Add 460 g of anhydrous ethanol (10 mol) to the product obtained in step (2), continuously stir and react at about 50 °C for 5 h, and then vacuum-remove the small-molecule compounds in the reaction system to obtain the product.

[0057] Example 3

[0058] A silane-capped polyether is prepared as follows:

[0059] (1) Under nitrogen conditions, add 800 g of diallyl-capped polypropylene glycol (molecular weight about 800, 1.0 mol), 750 g of amino-capped poly(dimethylsiloxane) (molecular weight about 1000, 0.75 mol) and 0.4 g of Speier catalyst, stir and mix well, and continuously stir and react at about 60 °C for 4 h to obtain a diallyl-capped propylene glycol-dimethylsiloxane copolymer, and the measured weight-average molecular weight is 6135;

[0060] (2) Add 129 g of ethyl dichlorosilane (1.0 mol) to the product obtained in step (1), continuously stir and react at about 80 °C for 6 h, and then vacuum-remove the small-molecule compounds in the reaction system;

[0061] (3) Add 460 g of anhydrous ethanol (10 mol) to the product obtained in step (2), continuously stir and react at about 30 °C for 5 h, and then vacuum-remove the small-molecule compounds in the reaction system to obtain the product.

[0062] Example 4

[0063] A silane - terminated polyether, and its preparation steps are as follows:

[0064] (1) Under nitrogen atmosphere, 720 g of diallyl - terminated polypropylene glycol (molecular weight about 600, 1.2 mol), 1100 g of amino - terminated poly(dimethylsiloxane) (molecular weight about 1000, 1.1 mol), 4.0 kg of 2,2,4 - trimethylpentane and 0.6 g of Speier catalyst are fully stirred and mixed, and continuously stirred at about 60 °C for 8 h to obtain a diallyl - terminated propylene glycol - dimethylsiloxane copolymer, and the measured weight - average molecular weight is 18365;

[0065] (2) 108.4 g of trichlorosilane (0.8 mol) is added to the product obtained in step (1), and continuously stirred at about 90 °C for 4 h, and then small - molecule compounds (including solvents) in the reaction system are removed by vacuum;

[0066] (3) 160 g of anhydrous methanol (5 mol) is added to the product obtained in step (2), and continuously stirred at about 20 °C for 5 h, and then small - molecule compounds in the reaction system are removed by vacuum, thus obtaining the product.

[0067] Example 5

[0068] A silane - terminated polyether, and its preparation steps are as follows:

[0069] (1) Under nitrogen atmosphere, 1600 g of diallyl - terminated polypropylene glycol (molecular weight about 4000, 0.4 mol), 100 g of amino - terminated poly(dimethylsiloxane) (molecular weight about 500, 0.2 mol) and 0.7 g of Karstedt catalyst are fully stirred and mixed, and continuously stirred at about 80 °C for 6 h to obtain a diallyl - terminated propylene glycol - dimethylsiloxane copolymer, and the measured weight - average molecular weight is 8469;

[0070] (2) 135.5 g of trichlorosilane (1.0 mol) is added to the product obtained in step (1), and continuously stirred at about 70 °C for 4 h, and then small - molecule compounds in the reaction system are removed by vacuum;

[0071] (3) 192 g of anhydrous methanol (6 mol) is added to the product obtained in step (2), and continuously stirred at about 40 °C for 5 h, and then small - molecule compounds in the reaction system are removed by vacuum, thus obtaining the product.

[0072] Example 6

[0073] A silane - terminated polyether, and its preparation steps are as follows:

[0074] (1) Under nitrogen atmosphere, 1200 g of diallyl-terminated polypropylene glycol (molecular weight about 1000, 1.2 mol), 500 g of amino-terminated poly(dimethylsiloxane) (molecular weight about 500, 1.0 mol), 5.0 kg of n-hexane and 0.8 g of Speier catalyst were thoroughly stirred and mixed, and continuously stirred at about 70 °C for 4 h to obtain a diallyl-terminated propylene glycol-dimethylsiloxane copolymer, with the measured weight-average molecular weight being 17620;

[0075] (2) 46 g of methyldichlorosilane (0.4 mol) was added to the product obtained in step (1), and continuously stirred at about 70 °C for 6 h, and then small-molecule compounds (including solvents) in the reaction system were removed under vacuum;

[0076] (3) 128 g of anhydrous methanol (4 mol) was added to the product obtained in step (2), and continuously stirred at about 40 °C for 3 h, and then small-molecule compounds in the reaction system were removed under vacuum to obtain the product.

[0077] Example 7

[0078] A silane-terminated polyether, and its preparation steps are as follows:

[0079] (1) Under nitrogen atmosphere, 600 g of diallyl-terminated polypropylene glycol (molecular weight about 1000, 0.6 mol), 1000 g of amino-terminated poly(dimethylsiloxane) (molecular weight about 2000, 0.5 mol), 2.0 kg of methylcyclohexane and 1.0 g of Speier catalyst were thoroughly stirred and mixed, and continuously stirred at about 70 °C for 5 h to obtain a diallyl-terminated propylene glycol-dimethylsiloxane copolymer, with the measured weight-average molecular weight being 16254;

[0080] (2) 57.5 g of methyldichlorosilane (0.5 mol) was added to the product obtained in step (1), and continuously stirred at about 80 °C for 5 h, and then small-molecule compounds (including solvents) in the reaction system were removed under vacuum;

[0081] (3) 96 g of anhydrous methanol (3 mol) was added to the product obtained in step (2), and continuously stirred at about 40 °C for 4 h, and then small-molecule compounds in the reaction system were removed under vacuum to obtain the product.

[0082] Example 8

[0083] A silane-terminated polyether, and its preparation steps are as follows:

[0084] (1) Under nitrogen atmosphere, 1200 g of diallyl-terminated polypropylene glycol (molecular weight about 2000, 0.6 mol), 750 g of amino-terminated poly(dimethylsiloxane) (molecular weight about 1500, 0.5 mol), 9.5 kg of n-octane and 1.2 g of Karstedt catalyst were fully stirred and mixed, and continuously stirred and reacted at about 80 °C for 6 h to obtain diallyl-terminated propylene glycol-dimethylsiloxane copolymer, and the measured weight-average molecular weight was 19687;

[0085] (2) 77.4 g of ethyl dichlorosilane (0.6 mol) was added to the product obtained in step (1), and continuously stirred and reacted at about 90 °C for 8 h, and then small molecule compounds (including solvents) in the reaction system were removed under vacuum;

[0086] (3) 96 g of anhydrous methanol (3 mol) was added to the product obtained in step (2), and continuously stirred and reacted at about 30 °C for 5 h, and then small molecule compounds in the reaction system were removed under vacuum to obtain the product.

[0087] Example 9

[0088] A silane-terminated polyether, and its preparation steps are as follows:

[0089] (1) Under nitrogen atmosphere, 600 g of diallyl-terminated polypropylene glycol (molecular weight about 2000, 0.3 mol), 1200 g of amino-terminated poly(dimethylsiloxane) (molecular weight about 6000, 0.2 mol), 6.0 kg of toluene and 1.2 g of Speier catalyst were fully stirred and mixed, and continuously stirred and reacted at about 90 °C for 5 h to obtain diallyl-terminated propylene glycol-dimethylsiloxane copolymer, and the measured weight-average molecular weight was 18054;

[0090] (2) 92 g of methyl dichlorosilane (0.8 mol) was added to the product obtained in step (1), and continuously stirred and reacted at about 90 °C for 4 h, and then small molecule compounds (including solvents) in the reaction system were removed under vacuum;

[0091] (3) 128 g of anhydrous methanol (4 mol) was added to the product obtained in step (2), and continuously stirred and reacted at about 50 °C for 1 h, and then small molecule compounds in the reaction system were removed under vacuum to obtain the product.

[0092] Example 10

[0093] A silane-terminated polyether, and its preparation steps are as follows:

[0094] (1) Under nitrogen conditions, 960 g of diallyl-terminated polypropylene glycol (molecular weight about 800, 1.2 mol), 450 g of amino-terminated poly(dimethylsiloxane) (molecular weight about 500, 0.9 mol) and 1.0 g of Karstedt catalyst were fully stirred and mixed, and continuously stirred and reacted at about 60 °C for 8 h to obtain a diallyl-terminated propylene glycol-dimethylsiloxane copolymer, and the measured weight-average molecular weight was 4664;

[0095] (2) 135.5 g of trichlorosilane (1.0 mol) was added to the product obtained in step (1), and continuously stirred and reacted at about 80 °C for 5 h, and then small-molecule compounds in the reaction system were removed under vacuum;

[0096] (3) 460 g of absolute ethanol (10 mol) was added to the product obtained in step (2), and continuously stirred and reacted at about 40 °C for 3 h, and then small-molecule compounds in the reaction system were removed under vacuum to obtain the product.

[0097] From the above molecular weight measurement results, it can be seen that through the method of the present invention, polyethers with lower molecular weights can be chain-extended to obtain products with higher molecular weights, avoiding the difficulties of synthesizing high-molecular-weight polyethers and desalting.

[0098] Comparative example 1 is the silane-terminated polyether product Excestar TM S2420E of AGC Chemicals Co., Ltd., and its main chain is a pure polyether chain.

[0099] Comparative example 2 is the silane-terminated polyether product STP-E 35 of Wacker Chemie, which contains a urethane group.

[0100] Application example

[0101] The silane-terminated polyethers in the above examples and comparative examples were made into sealants according to the following steps:

[0102] (1) In a double planetary mixer, 100 parts of silane-terminated polyether, 70 parts of plasticizer (DIUP), 3 parts of deforming agent (Dehydat 8312), 1.5 parts of ultraviolet absorber (Tinuvin 326), and 1.5 parts of light stabilizer (LS-770) were added and stirred at room temperature for 10 min (dispersion speed: 0, scraper speed: 50 rpm);

[0103] (2) Add 220 parts of calcium carbonate (Carbital 110S), 10 parts of titanium dioxide (Bayer RFK-2), and 20 parts of thixotropic agent (Crayvallac Super), stir at room temperature for 10 min (dispersion speed: 500 rpm, scraper speed: 50 rpm), and then evacuate and stir at room temperature (gauge pressure < -0.09 MPa) for 30 min (dispersion speed: 1000 rpm, scraper speed: 100 rpm);

[0104] (3) Then, at 110 °C, evacuate (gauge pressure < -0.09 MPa) and stir for 1.5 h (dispersion speed: 1000 rpm, scraper speed: 100 rpm);

[0105] (4) Stir (dispersion speed: 500 rpm, scraper speed: 50 rpm) and cool to below 50 °C;

[0106] (5) Add 3 parts of dehydrating agent (VTMO) and stir at room temperature for 10 min (dispersion speed: 500 rpm, scraper speed: 50 rpm);

[0107] (6) Add 2 parts of adhesion promoter (DAMO) and stir at room temperature for 10 min (dispersion speed: 500 rpm, scraper speed: 50 rpm);

[0108] (7) Add 1 part of curing catalyst (U220H) and stir at room temperature for 10 min (dispersion speed: 500 rpm, scraper speed: 50 rpm);

[0109] (8) Evacuate and stir at room temperature (gauge pressure < -0.09 MPa) for 5 min (dispersion speed: 500 rpm, scraper speed: 50 rpm) to complete the preparation of the sealant. (Note: The parts in the above application examples are all parts by weight.)

[0110] Tested according to the standard of "GB / T 14683-2017 Silicone and Modified Silicone Building Sealants", some of the test results are shown in the following table:

[0111]

[0112] Judging from the above test results, all the sealants prepared from the silane-terminated polyether synthesized by the method of the present invention meet the requirements of modified silicone building sealants (MS) in the national standard, and all performance indicators are comparable to those of the products of AGC and Wacker.

[0113] Another part of the test results are shown in the following table:

[0114] Sample Adhesiveness after ultraviolet irradiation Adhesiveness after immersion in water and exposure to light Comparative Example 1 Failure Failure Comparative Example 2 Failure Failure Example 1 No failure No failure Example 2 No failure No failure Example 3 No failure No failure Example 4 No failure No failure Example 5 Failure Failure Example 6 No failure No failure Example 7 No failure No failure Example 8 No failure No failure Example 9 No failure No failure Example 10 No failure No failure

[0115] As can be seen from the above results, Comparative Example 1 and Comparative Example 2 do not meet the requirements of silicone building sealant (SR) in the national standard, proving that their anti-aging and weather resistance are poor. For the sealant prepared from the product synthesized by the method of the present invention, only Example 5 fails to meet this requirement because the content of polyether segments in it is relatively high, while other examples all have good anti-aging and weather resistance. Therefore, the silane-terminated polyether synthesized by the method of the present invention has higher flexibility in terms of product anti-aging and weather resistance.

[0116] In summary, the above are only the preferred embodiments of the present invention, and are not used to limit the scope of implementation of the present invention. All equivalent changes and modifications made according to the shape, structure, features and spirit described in the scope of the claims of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A silane-terminated polyether, characterized in that: The silane-terminated polyether has a structure represented by the following general formula (I): Where: m is a number between 4 and 80; n is a number between 5 and 80; x is a number between 1 and 20; R 1 is Me, Et, OMe or OEt; R 2 is OMe or OEt; The molecular weight of the entire molecule is 2000-20000.

2. A silane-terminated polyether and a preparation method thereof, characterized in that: The following steps are involved: Step (1): Under nitrogen conditions, fully stir and mix bisallyl-terminated polypropylene glycol, hydrogen-terminated poly(dimethylsiloxane) and a platinum catalyst, and continue stirring and reacting at 60 to 90° C. for 4 to 8 hours to obtain a bisallyl-terminated propylene glycol-dimethylsiloxane copolymer. The reaction formula of step (1) is as follows: Step (2): adding a hydrogen-containing silane compound to the bis-allyl-terminated propylene glycol-dimethylsiloxane copolymer obtained in step (1), stirring and reacting at 60 to 90° C. for 4 to 8 hours, and then removing the small molecule compounds in the reaction system under vacuum. The reaction formula of step (2) is as follows: Step (3): adding anhydrous methanol or ethanol to the reaction product obtained in step (2), stirring and reacting at 20 to 50° C. for 1 to 5 hours, and then removing the small molecule compounds in the reaction system under vacuum to obtain a silane-terminated polyether. The reaction formula of step (3) is as follows: Where R 3 is Me, Et or Cl, and the other groups and degree of polymerization are as described in claim 1; The bisallyl-terminated polypropylene glycol has a structure represented by the following general formula (II): Where m is a number between 4 and 80; The hydrogen-terminated poly(dimethylsiloxane) has a structure represented by the following general formula (III): Where n is a number between 5 and 80; The platinum catalyst is a Speier catalyst or a Karstedt catalyst, and the amount of platinum used in the reaction system of step (1) is 5 to 20 ppm of the total amount of the reaction raw materials; The hydrogen-containing silane compound is methyldichlorosilane, ethyldichlorosilane or trichlorosilane, and its amount is 2.1 to 8 times the molar amount of the bis-allyl-terminated propylene glycol-dimethylsiloxane copolymer obtained in step (1).

3. A silane-terminated polyether and a preparation method thereof according to claim 2, characterized in that: In the step (1), the molar ratio of the bisallyl-terminated polypropylene glycol to the hydrogen-terminated poly(dimethylsiloxane) is (x+1):x, wherein x is a number between 1 and 20.

4. A silane-terminated polyether and a preparation method thereof according to claim 2, characterized in that: In the step (1), adding anhydrous solvent to dilute the entire reaction system is beneficial to the chain extension of step (1) and the hydrosilylation of step (2).

5. A silane-terminated polyether and a preparation method thereof according to claim 4, characterized in that: The anhydrous solvent is selected from alkanes, cycloalkanes, aromatic hydrocarbons, or mixtures thereof having 6 to 8 carbon atoms.

6. A silane-terminated polyether and a preparation method thereof according to claim 4, characterized in that: The feed ratio of the anhydrous solvent to the total weight of the bisallyl-terminated polypropylene glycol and the hydrogen-terminated poly(dimethylsiloxane) in step (1) of the method of the present invention is (0.5-5):

1.

7. A silane-terminated polyether and a preparation method thereof according to claim 2, characterized in that: In the step (3), the amount of anhydrous methanol or ethanol used is 10 to 50 times the molar amount of the bis-allyl-terminated propylene glycol-dimethylsiloxane copolymer obtained in the step (1).

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