Preparation method of amino silane oligomer

Abstract

The invention discloses a preparation method of an aminosilane oligomer, and belongs to the technical field of fine chemical engineering. The preparation method of the amino silane oligomer comprises the following steps: firstly, carrying out hydrolysis reaction on alkyl alkoxy silane to obtain an alkyl alkoxy silane hydrolysate; then amino silane is added into the alkyl alkoxy silane hydrolysate for a hydrolytic amination reaction, and after the reaction is completed, normal-pressure distillation and negative-pressure distillation are sequentially carried out to obtain the amino silane oligomer, the amino silane oligomer prepared by the invention has the characteristics of high flash point, low viscosity, light color, transparency, low total chlorine and the like.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a method for preparing an aminosilane oligomer. Background Art

[0002] Since its introduction, silane oligomers have been widely used in electronics, electrical appliances, transportation, aerospace, construction, textiles, papermaking, leather, food, medicine, health and other fields with their unique organic and inorganic structures, excellent high and low temperature resistance, weather resistance, dielectric properties, low surface tension, physiological inertness, and easy processing. They are a new type of "green material" with great development prospects. At present, there are many aminosilane polymer products on the market, but most of them have complex synthesis routes, are prone to yellowing during production and application, and have no requirements for their flash points. However, some flash points have a great impact on transportation, and some manufacturers have certain requirements for flash points. Therefore, it is necessary to improve them.

[0003] Chinese patent document CN109762011A discloses a method for preparing a functional aminosilane oligomer. The invention comprises the following steps: hydrolyzing chloropropyl alkoxysilane, aminating the chloropropyl alkoxysilane hydrolysate with aminosilane, and hydrolyzing the aminosilane, and then using sodium alcoholate to carry out a dechlorination reaction. After the reaction is completed, low-boiling distillation and filtering steps are performed to obtain a light-colored, transparent, low-viscosity, and low-free-chlorine functional aminosilane oligomer product. The molar yield of the product prepared by the invention reaches more than 99.0%, which can effectively solve the yellowing problem of existing aminosilane polymer products and is suitable for industrial-scale production; the invention is particularly suitable for improving the adhesion and wettability of polymers such as room temperature vulcanized silicone rubber, two-component polyurethane, silicone-modified polyurethane, silicone-modified polyether, and two-component epoxy resin to inorganic surfaces and plastic surfaces; the reaction of the invention involves steps such as hydrolysis, amination, and dechlorination, and the process is complicated, which is not conducive to large-scale industrial production. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for preparing an aminosilane oligomer that effectively solves the problems of low flash point and easy yellowing of aminosilane polymers, can be industrially produced, has low volatility, good aging resistance, low environmental pollution, and lower VOC emissions. The present invention simplifies the synthesis method, omits the process of dripping alkylsilane hydrolyzate into aminosilane, which makes the degree of polymerization difficult to control, and obtains an aminosilane oligomer with a flash point > 50°C, which is conducive to saving transportation costs.

[0005] To achieve the above-mentioned object, the present invention provides a method for preparing an aminosilane oligomer, comprising the following steps: firstly subjecting an alkyl alkoxy silane to a hydrolysis reaction to obtain an alkyl alkoxy silane hydrolyzate; then adding aminosilane to the alkyl alkoxy silane hydrolyzate to carry out a hydrolysis and amination reaction, and after the reaction is completed, sequentially performing atmospheric distillation and negative pressure distillation to obtain the aminosilane oligomer.

[0006] Preferably, the molar ratio of the alkylalkoxysilane to the aminosilane is 1:0.4-0.6.

[0007] Preferably, the preparation method of the alkylalkoxysilane hydrolyzate is as follows:

[0008] Alkyl alkoxy silane and solvent are mixed to obtain a mixed solution, which is heated, a catalyst is added, and then a mixed solution of water and solvent is added dropwise to the mixed solution; after the addition is completed, the mixture is heated and reacted to obtain a hydrolyzate of alkyl alkoxy silane.

[0009] Further preferably, the alkyl alkoxysilane is at least one of propyltrimethoxysilane, propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-octyltrimethoxysilane and n-octyltriethoxysilane; and the total chlorine content in the alkyl alkoxysilane does not exceed 50 ppm.

[0010] More preferably, the solvent is methanol and / or ethanol.

[0011] More preferably, the catalyst is one of hydrochloric acid and ammonia water.

[0012] Further preferably, the molar ratio of alkylalkoxysilane to solvent in the mixed solution is 1:1-2; and the heating temperature is 60-80°C.

[0013] Further preferably, the molar ratio of water to solvent in the mixed solution is 1:0.5-1.5.

[0014] Further preferably, the condition for judging that the water reaction is complete is: the water content in the crude product is below 100 ppm; the degree of polymerization of the reaction can be controlled by the amount of water added.

[0015] Preferably, the hydrolysis amination reaction process is as follows:

[0016] Aminosilane is added to the hydrolyzate of alkylalkoxysilane, and a mixed solution of water and a solvent is added dropwise under heating and stirring conditions. After the addition is completed, heating is continued for reaction to obtain a crude aminosilane oligomer.

[0017] More preferably, the solvent is methanol and / or ethanol.

[0018] Further preferably, the reaction temperature is controlled at 50-65° C. during the dropwise addition; after the dropwise addition is completed, the reaction temperature is controlled at 70-80° C. and the reaction is continued for 0.5-2 h to obtain a crude aminosilane oligomer.

[0019] Further preferably, the criterion for judging whether the water reaction is complete is that the water content in the hydrolyzate is below 100 ppm.

[0020] Preferably, the negative pressure during the negative pressure distillation process is ≥800 mmHg.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention performs a first step of hydrolysis of alkyl alkoxy silane to obtain an alkyl alkoxy silane hydrolyzate, and then adds amino silane to the alkyl alkoxy silane hydrolyzate to perform hydrolysis and amination reactions. After the reaction is completed, the solvent is subjected to desolvation processes such as atmospheric distillation and negative pressure distillation to finally obtain a light-colored, transparent, low-viscosity, and low-total-chlorine amino silane oligomer. The invention can effectively solve the problems of yellowing and low flash point of existing aminosilane polymer products, and is suitable for industrial-scale production. Compared with commercially available aminosilane oligomers, the synthesized product has the advantages of lower VOC emission, strong adhesion, multi-functionality, low yellowing, excellent water resistance and the like, and can be widely used in the fields of coatings, adhesives, sealants, plastics, powders and metals. The synthesized product of the invention has super strong organic wettability on the interface of materials, can form strong weather resistance and strong moisture resistance with the surface of the adhesion material, and has excellent hydrophobicity, and is particularly suitable for improving the adhesion and wettability of polymers such as room temperature vulcanized silicone rubber, two-component polyurethane, silicone-modified polyurethane, silicone-modified polyether, two-component epoxy resin and inorganic surfaces and plastic surfaces. DETAILED DESCRIPTION

[0023] To avoid redundancy, the items used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0024] Example 1

[0025] A method for preparing an aminosilane oligomer comprises the following steps:

[0026] In a flask equipped with a magnetic stirrer, a thermometer, and a constant pressure dropping funnel, 328 g of propyltrimethoxysilane and 64 g of methanol were added, mixed and stirred evenly, heated to 60°C, 0.06 g of a 10 wt% dilute hydrochloric acid aqueous solution was added, and then a mixture of 18 g of water and 32 g of methanol was added dropwise. During the dropping process, the reaction temperature was controlled to be 60-80°C. After the dropping was completed, the reaction temperature was controlled to be 75°C. The reaction was continued for 1 hour. After the reaction was completed, the system temperature was lowered to 50°C to obtain a propyltrimethoxysilane hydrolyzate;

[0027] 177.6 g of γ-aminoethylaminopropyltrimethoxysilane was added to the hydrolyzate of propyltrimethoxysilane, and a mixed solution of 5.76 g of water and 20.48 g of methanol was added dropwise at 60°C. After the addition was completed, the reaction was continued at 75°C for 1 hour. After the reaction was completed, the crude product was cooled to room temperature; the solvent in the crude product was distilled, the temperature was gradually increased to control the temperature at 100°C to cut off the flow, and then cooled to room temperature; negative pressure was drawn to the flask, and the negative pressure was maintained above 800 mmHg, the magnetic stirrer was turned on, the heating device was turned on, the temperature was gradually increased to 60°C to cut off the flow, the negative pressure was released, and the temperature was cooled to room temperature to obtain 362 g of aminosilane oligomer.

[0028] After testing and analysis, the product viscosity is 32mPa·S, the color is 10 black Zeng, the flash point is 51℃, and the total chlorine content is 40ppm.

[0029] Example 2

[0030] A method for preparing an aminosilane oligomer comprises the following steps:

[0031] In a flask equipped with a magnetic stirrer, a thermometer, and a constant pressure dropping funnel, 412 g of propyltriethoxysilane and 92 g of ethanol were added and mixed and stirred evenly, heated to 60°C, 0.06 g of 10 wt% ammonia water was added, and then a mixture of 18 g of water and 46 g of ethanol was added dropwise. During the dropping process, the reaction temperature was controlled to be 60-80°C. After the dropping was completed, the reaction temperature was controlled to be 80°C. The reaction was continued for 2 hours. After the reaction was completed, the system temperature was lowered to 50°C to obtain a propyltriethoxysilane hydrolyzate;

[0032] 264g of γ-aminoethylaminopropyltrimethoxysilane was added to the hydrolyzate of propyltriethoxysilane, and a mixed solution of 7.2g of water and 36.8g of ethanol was added dropwise at 60°C. After the addition was completed, the reaction was continued at 70°C for 1h. After the reaction was completed, the crude product was cooled to room temperature; the solvent in the crude product was distilled, the temperature was gradually increased to control the temperature at 100°C to cut off the flow, and then cooled to room temperature; negative pressure was drawn to the flask, and the negative pressure was maintained at 900mmHg, the magnetic stirrer was turned on, the heating device was turned on, the temperature was gradually increased to 60°C to cut off the flow, the negative pressure was released, and the temperature was cooled to room temperature to obtain 441g of aminosilane oligomer.

[0033] After testing and analysis, the product viscosity is 56mPa·S, the color is 15 black Zeng, the flash point is 55℃, and the total chlorine content is 35ppm.

[0034] Example 3

[0035] A method for preparing an aminosilane oligomer comprises the following steps:

[0036] In a flask equipped with a magnetic stirrer, a thermometer, and a constant pressure dropping funnel, 412 g of propyltriethoxysilane and 92 g of ethanol were added and mixed and stirred evenly, heated to 60°C, 0.06 g of 10 wt% ammonia water was added, and then a mixture of 18 g of water and 46 g of ethanol was added dropwise. During the dropping process, the reaction temperature was controlled to be 60-80°C. After the dropping was completed, the reaction temperature was controlled to be 80°C. The reaction was continued for 2 hours. After the reaction was completed, the system temperature was lowered to 50°C to obtain a propyltriethoxysilane hydrolyzate;

[0037] 265.2g of aminopropyltriethoxysilane was added to the hydrolyzate of propyltriethoxysilane, and a mixed solution of 8.64g of water and 44.16g of ethanol was added dropwise at 60°C. After the addition was completed, the reaction was continued at 70°C for 1h. After the reaction was completed, the crude product was cooled to room temperature; the solvent in the crude product was distilled, the temperature was gradually increased to control the temperature at 100°C to cut off the flow, and then cooled to room temperature; negative pressure was drawn into the flask, and the negative pressure was maintained at 1000mmHg, the magnetic stirrer was turned on, the heating device was turned on, the temperature was gradually increased to 60°C to cut off the flow, the negative pressure was released, and the temperature was cooled to room temperature to obtain 428g of aminosilane oligomer.

[0038] After testing and analysis, the product viscosity is 43mPa·S, the color is 10 black Zeng, the flash point is 54℃, and the total chlorine content is 33ppm.

[0039] The commercially available aminosilane oligomer was tested and analyzed, and the test results were as follows: chromaticity: 10 black cm, viscosity: 32 mPa·S, flash point: 27° C., and total chlorine content: 1000 ppm. By comparing the experimental results, it can be seen that the aminosilane oligomer prepared by the present invention improves the flash point of the aminosilane oligomer, which is beneficial to improving the safety during transportation.

[0040] The wettability index is determined by measuring the contact angle θ (the angle between the solid-liquid interface and the liquid interior to the gas-liquid interface). The smaller the contact angle θ, the better the wetting effect. If θ=0, the liquid completely wets the solid surface. Two drops of Example 1 and a commercially available aminosilane oligomer were dropped on a PVC plate, and the contact angle θ was measured. The experimental results showed that the contact angle θ of the aminosilane oligomer prepared in Example 1 was 2°, and the contact angle θ of the commercially available aminosilane oligomer was 25°.

[0041] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A method for preparing an aminosilane oligomer, characterized in that: The method comprises the following steps: firstly subjecting alkyl alkoxy silane to a hydrolysis reaction to obtain an alkyl alkoxy silane hydrolysate; then adding amino silane to the alkyl alkoxy silane hydrolysate to carry out a hydrolysis and amination reaction, and after the reaction is completed, sequentially carrying out atmospheric pressure distillation and negative pressure distillation to obtain the amino silane oligomer.

2. The preparation method according to claim 1, characterized in that: The molar ratio of the alkylalkoxysilane to the aminosilane is 1:0.4-0.

6.

3. The preparation method of subject 1 according to claim 1, characterized in that: The preparation method of the alkyl alkoxysilane hydrolyzate is as follows: alkyl alkoxysilane and a solvent are mixed to obtain a mixed solution, heated, a catalyst is added, and then a mixed solution of water and a solvent is dripped into the mixed solution; after the dripping is completed, heating is continued for reaction to obtain the alkyl alkoxysilane hydrolyzate.

4. The preparation method according to claim 1 or 3, characterized in that: The alkyl alkoxysilane is at least one of propyl trimethoxysilane, propyl triethoxysilane, n-butyl trimethoxysilane, n-butyl triethoxysilane, isobutyl trimethoxysilane, isobutyl triethoxysilane, n-octyl trimethoxysilane and n-octyl triethoxysilane; and the total chlorine content in the alkyl alkoxysilane does not exceed 50 ppm.

5. The preparation method according to claim 3, characterized in that: The solvent is methanol and / or ethanol.

6. The preparation method according to claim 3, characterized in that: The catalyst is one of hydrochloric acid and ammonia water.

7. The preparation method according to claim 3, characterized in that: The molar ratio of alkylalkoxysilane to solvent in the mixed solution is 1:1-2; and the heating temperature is 60-80°C.

8. The preparation method according to claim 3, characterized in that: The molar ratio of water to solvent in the mixed solution is 1:0.5-1.

5.

9. The preparation method according to claim 1, characterized in that: The hydrolysis amination reaction process is as follows: Aminosilane is added to the hydrolyzate of alkylalkoxysilane, and a mixed solution of water and a solvent is added dropwise under heating and stirring conditions. After the addition is completed, heating is continued for reaction to obtain a crude aminosilane oligomer.

10. The preparation method according to claim 1, characterized in that: The negative pressure during the negative pressure distillation process is ≥800 mmHg.