Polyether modified organic silicon defoaming agent and preparation method thereof

Abstract

The invention relates to the technical field of defoaming agents, and discloses a polyether modified organic silicon defoaming agent and a preparation method thereof. The polyether modified organic silicon defoaming agent is prepared from the following raw materials in parts by mass: 10 to 30 parts of polyether modified organic silicon, 20 to 40 parts of simethicone, 2 to 5 parts of modified mesoporous silicon dioxide, 2 to 4 parts of a thickening agent, 6 to 10 parts of an emulsifying agent and 35 to 55 parts of deionized water. The preparation method comprises the following steps: firstly, synthesizing hydrogen-terminated organic silicon with a hyperbranched structure, then synthesizing polyether containing a double-bond structure, and connecting the hydrogen-terminated organic silicon and the polyether with a hydrosilylation method to synthesize polyether modified organic silicon; secondly, synthesizing mesoporous silica with an amino group on the surface, and grafting the fluorine-containing chain segment on the mesoporous silica to synthesize modified mesoporous silica; by adopting the synergistic effect of the two components, the defoaming and foam inhibiting properties of a matrix in the foaming liquid are improved, and meanwhile, the foaming liquid has very good wettability and stability.

Description

Technical Field

[0001] The invention relates to the technical field of defoamers, and in particular to a polyether-modified organosilicon defoamer and a preparation method thereof. Background Art

[0002] In the process of coating construction, in order to reduce the generation of foam and the traces of bubbles left behind and form a beautiful coating film, defoamers must be used in the coating. Defoamers can also improve the gloss and durability of the coating film, as well as the fluidity of the coating and the dispersibility of the pigment. Common defoamers on the market include polyethers, organics, silicones, and polyether-modified silicones. Among them, polyether-modified silicone defoamers have the advantages of both polyether defoamers and silicone defoamers. They are a new type of high-efficiency defoamer that not only has the characteristics of polysiloxane defoamers, such as strong defoaming effect, low surface tension, low volatility, non-toxicity, no pollution, and physiological inertness, but also has the characteristics of polyether defoamers, such as high temperature resistance, acid and alkali resistance, etc.

[0003] Traditional polyether-modified silicone defoamers are mostly based on linear polysiloxane molecules as hydrophobic segments. The linear structure has limited dispersibility and compatibility in solution, while hyperbranched polymers with more branched structures have good dispersibility and compatibility in solution. In addition, adding nanoparticles to the defoamer system can further improve dispersibility, reduce the surface tension of the solution, and improve the defoaming and anti-foaming performance of the defoamer. Based on this, the present application develops a polyether-modified silicone defoamer with long anti-foaming time, fast defoaming speed, good stability and good compatibility. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a polyether-modified organosilicon defoamer and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A polyether-modified organic silicon defoamer comprises the following raw materials in mass fractions: 10-30 parts of polyether-modified organic silicon, 20-40 parts of dimethyl silicone oil, 2-5 parts of modified mesoporous silica, 2-4 parts of thickener, 6-10 parts of emulsifier, and 35-55 parts of deionized water;

[0007] The polyether-modified silicone is prepared by the following steps:

[0008] Step A1, tri(pentafluorophenyl)borane is stirred and mixed in a reactor containing cyclohexane, and then ethyl orthosilicate and dimethyldimethoxysilane are slowly added dropwise to the reactor under stirring for 1.5-2.5 hours, and then 1,1,3,3-tetramethyldisiloxane is slowly added dropwise for 40-60 minutes. After the addition is completed, activated carbon and triethylamine are added to the mixture and stirred for 5 minutes. The mixture is filtered, rotary evaporated, concentrated, dried and fractionated under reduced pressure to obtain terminal hydrogen hyperbranched organosilicon;

[0009] Furthermore, the usage ratio of tri(pentafluorophenyl)borane, cyclohexane, ethyl orthosilicate, dimethyldimethoxysilane, 1,1,3,3-tetramethyldisiloxane, activated carbon and triethylamine is 0.05-0.1 g:500 mL:5.2-10.4 g:14.4-33.6 g:12-24 g:2-3 g:1.5-2.5 mL.

[0010] Step A2, methacryloyl chloride and toluene are mixed uniformly, recorded as solution A, 2-(aminomethyl)-1,3-propanediol and triethylamine are added to the reactor containing toluene, stirred and mixed uniformly, and solution A is slowly dripped into the reactor under ice-water bath and stirring conditions using a constant pressure dropping funnel. The dropping time is 3-4 hours. After the dropwise addition is completed, the reaction is carried out at room temperature for 12 hours. After the reaction is completed, the filtrate is filtered, collected, washed, and dried, and then filtered again, the filtrate is collected, and distilled under reduced pressure to obtain intermediate product 1;

[0011] Furthermore, the usage ratio of 2-(aminomethyl)-1,3-propanediol, triethylamine, toluene and solution A is 6-12 g:20-40 g:200 mL:20-40 mL, and the usage ratio of methacryloyl chloride and toluene in solution A is 23-46 g:20-40 mL.

[0012] Step A3, add the intermediate product 1 and potassium hydroxide into a reaction kettle, introduce nitrogen for 10 minutes, heat to 80-120°C under nitrogen conditions for reaction for 2-5 hours, cool to room temperature, add propylene oxide, stir and heat to 50-80°C for reaction for 3-6 hours, then lower the system temperature to 10-35°C, add ethylene oxide, stir and heat to 50-80°C for reaction for 3-6 hours, and after the reaction is completed, obtain a terminal double-bond polyether;

[0013] Furthermore, the usage ratio of the intermediate product 1, potassium hydroxide, propylene oxide and ethylene oxide is 13.5-27g: 0.7-1.5g: 20-40g: 8-16g.

[0014] Step A4, adding hydrogen-terminated hyperbranched organosilicon and chloroplatinic acid into a reactor, introducing nitrogen for 10 minutes, and heating to 75-95° C. under nitrogen conditions, adding the double-bond-terminated polyether dropwise using a constant pressure dropping funnel for 1-2 hours, and after the addition is completed, continuing the reaction for 2-4 hours, turning off the nitrogen, and performing reduced pressure distillation to obtain a polyether-modified silicone oil;

[0015] Furthermore, the usage ratio of the hydrogen-terminated hyperbranched silicone, the double-bond-terminated polyether and chloroplatinic acid is 10-20 g: 15-25 g: 0.5-0.8 g.

[0016] The modified mesoporous silica is prepared by the following steps:

[0017] Step B1, stir and mix hexadecyltrimethylammonium bromide in deionized water, add 0.1 mol / L hydrochloric acid and stir for 30 minutes, then add ethyl orthosilicate and γ-aminopropyltriethoxysilane and stir and mix evenly, let stand for 2 hours, heat to 60-80°C and stir for 8-12 hours, after the reaction is completed, centrifuge, wash and dry, and then disperse the obtained product in a mixed solution of 20 mL of ethanolamine and 80 mL of ethanol, reflux extract at 90°C for 12 hours, centrifuge, wash and dry, and then repeat the extraction once to obtain mesoporous silica;

[0018] Furthermore, the usage ratio of hexadecyltrimethylammonium bromide, deionized water, hydrochloric acid, ethyl orthosilicate and γ-aminopropyltriethoxysilane is 0.6-0.9 g: 60 mL: 4-6 g: 3-4.5 mL: 0.2-0.4 mL.

[0019] Step B2, adding mesoporous silica to a reactor containing deionized water, ultrasonically treating for 30 minutes, adjusting the pH of the mixed solution to 8.5, adding 2H, 2H-perfluorooctanoic acid and ultrasonically treating for 30 minutes, and then reacting for 8-12 hours under nitrogen conditions at a reaction temperature of 70-90° C. After the reaction is completed, cooling to room temperature, centrifuging, washing and drying to obtain modified mesoporous silica;

[0020] Furthermore, the usage ratio of mesoporous silica, 2H,2H-perfluorooctanoic acid and deionized water is 0.5-1 g: 0.1-0.3 g: 50 mL.

[0021] A method for preparing a polyether-modified silicone defoamer comprises the following steps:

[0022] Weigh the raw materials by weight, mix and stir the polyether-modified silicone, dimethyl silicone oil, modified mesoporous silica and thickener evenly, raise the temperature to 100-160°C, continue stirring for 30 minutes, then add the emulsifier and deionized water and stir for 5-10 minutes to obtain the polyether-modified silicone defoamer.

[0023] Beneficial effects of the present invention:

[0024] The polyether-modified organic silicon defoamer of the present invention comprises the following steps: firstly, synthesizing a hydrogen-terminated organic silicon with a hyperbranched structure, then synthesizing a polyether containing a double bond structure, and connecting the two by a hydrosilylation method to synthesize the polyether-modified organic silicon; secondly, synthesizing a mesoporous silica containing an amino group on the surface by using tetraethyl orthosilicate and γ-aminopropyltriethoxysilane as silicon sources and hexadecylammonium bromide as a template, and then introducing a fluorine-containing chain segment into the mesoporous silica to synthesize the modified mesoporous silica; utilizing the synergistic effect between the two to improve the defoaming and anti-foaming performance of the substrate in the foaming liquid, and at the same time having good wettability and stability.

[0025] In the polyether-modified silicone, firstly, ethyl orthosilicate, dimethyldimethoxysilane and 1,1,3,3-tetramethyldisiloxane were used as silicon sources for synthesizing silicone, and tri(pentafluorophenyl)borane was used as a catalyst to synthesize a hyperbranched silicone containing terminal hydrogen bonds; secondly, the intermediate product 1 was synthesized by the reaction between the amino group in 2-(aminomethyl)-1,3-propanediol and the acyl chloride group in methacryloyl chloride; thirdly, the intermediate product 1, propylene oxide and ethylene oxide were used as raw materials and potassium hydroxide was used as a catalyst to synthesize a terminal double-bond polyether; finally, the terminal double-bond polyether was grafted onto the terminal hydrogen hyperbranched silicone by the hydrosilylation method to synthesize the polyether-modified silicone oil. The polyether-modified silicone contains hydrophilic groups: amide groups, polyether segments and ethylene oxide, which enhance the hydrophilic properties of the defoamer, improve its dispersibility, emulsification and stability in water, and increase the defoaming effect of the matrix; it contains hydrophobic groups: polysiloxane and propylene oxide, which enhance the insolubility of the defoamer, reduce the formation of foam, and improve the defoaming and anti-foaming properties of the defoamer; it has a hyperbranched structure, which can spread rapidly on the gas-liquid interface of the foaming system, locally invade and break the foam, and has better defoaming activity; in addition, under the synergistic effect of polyether and silicone, the polyether-modified silicone defoamer can make the solution have a lower surface tension, so that the defoamer can be dispersed and spread faster on the surface of the solution, accelerate the breaking of foam, and has good wetting properties.

[0026] In the modified mesoporous silica, firstly, mesoporous silica with amino groups on the surface is synthesized using tetraethyl orthosilicate and γ-aminopropyltriethoxysilane as silicon sources and hexadecyl ammonium bromide as a template; secondly, the amino groups on the surface of the mesoporous silica react with the carboxyl groups in 2H, 2H-perfluorooctanoic acid to synthesize the modified mesoporous silica. The modified mesoporous silica acts as a nanodispersant in the system and can spread rapidly in the foaming liquid, thereby improving the dispersion efficiency and defoaming effect of the matrix; the mesoporous silica has a three-dimensional network structure, which can generate a large adsorption force, impact the bubbles, and thus cause the bubbles to burst, and its pore structure can also adsorb the gas in the foaming liquid to reduce the generation of bubbles; the introduction of fluorine-containing segments further reduces the surface tension of the solution, thereby improving the defoaming and anti-foaming effects of the matrix. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] 1) The polyether-modified silicone is prepared by the following steps:

[0030] Step A1, 0.05g of tris(pentafluorophenyl)borane was stirred and mixed in a reactor containing 500mL of cyclohexane, and then 5.2g of ethyl orthosilicate and 14.4g of dimethyldimethoxysilane were slowly added dropwise to the above reactor under stirring for 1.5h, and then 12g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise for 40min. After the addition was completed, 2g of activated carbon and 1.5mL of triethylamine were added to the mixture and stirred for 5min. The mixture was filtered, rotary evaporated, concentrated, dried and fractionated under reduced pressure to obtain terminal hydrogen hyperbranched organosilicon;

[0031] Step A2, 23g of methacryloyl chloride and 20mL of benzene were mixed uniformly, recorded as solution A, 6g of 2-(aminomethyl)-1,3-propanediol and 20g of triethylamine were added to a reactor containing 200mL of toluene and stirred to mix uniformly, 20mL of solution A was slowly dripped into the reactor under ice-water bath and stirring conditions using a constant pressure dropping funnel, the dropping time was 3h, after the addition was completed, the reaction was carried out at room temperature for 12h, after the reaction was completed, the filtrate was collected, washed and dried, and then the filtrate was filtered again, the filtrate was collected, and the intermediate product 1 was obtained by distillation under reduced pressure;

[0032] Step A3, add 13.5g of intermediate product 1 and 0.7g of potassium hydroxide into a reactor, introduce nitrogen for 10min, heat to 80°C under nitrogen for 2h, cool to room temperature, add 20g of propylene oxide, stir and heat to 50°C for 3h, then lower the system temperature to 10°C, add 8g of ethylene oxide, stir and heat to 50°C for 3h, and after the reaction is completed, obtain a terminal double-bond polyether;

[0033] Step A4, add 10g of hydrogen-terminated hyperbranched silicone and 0.5g of chloroplatinic acid into the reactor, introduce nitrogen for 10min, and heat to 75°C under nitrogen conditions, and use a constant pressure dropping funnel to drop 15g of double-bond-terminated polyether for 1h. After the addition is completed, continue the reaction for 2h, turn off the nitrogen, and distill under reduced pressure to obtain polyether-modified silicone oil.

[0034] 2) The modified mesoporous silica is prepared by the following steps:

[0035] Step B1, 0.6g of hexadecyltrimethylammonium bromide was stirred and mixed in 60mL of deionized water, 4g of 0.1mol / L hydrochloric acid was added and stirred for 30min, and then 3mL of ethyl orthosilicate and 0.2mL of γ-aminopropyltriethoxysilane were added and stirred and mixed, and after standing for 2h, the mixture was heated to 60°C and stirred for 8h. After the reaction was completed, the mixture was centrifuged, washed and dried, and the obtained product was dispersed in a mixed solution of 20mL of ethanolamine and 80mL of ethanol, and refluxed and extracted at 90°C for 12h, centrifuged, washed and dried, and then the extraction was repeated once to obtain mesoporous silica;

[0036] Step B2, add 0.5g of mesoporous silica to a reactor containing 50mL of deionized water, ultrasonically treat for 30min, adjust the pH of the mixed solution to 8.5, add 0.1g of 2H,2H-perfluorooctanoic acid and ultrasonically treat for 30min, then react under nitrogen for 8h at a reaction temperature of 70°C. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to obtain modified mesoporous silica.

[0037] Example 2

[0038] 1) The polyether-modified silicone is prepared by the following steps:

[0039] Step A1, 0.075g of tris(pentafluorophenyl)borane was stirred and mixed in a reactor containing 500mL of cyclohexane, and then 7.8g of ethyl orthosilicate and 24g of dimethyldimethoxysilane were slowly added dropwise to the above reactor under stirring for 2h, and then 18g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise for 50min. After the addition was completed, 2.5g of activated carbon and 2mL of triethylamine were added to the mixture and stirred for 5min. The mixture was filtered, rotary evaporated, concentrated, dried and fractionated under reduced pressure to obtain terminal hydrogen hyperbranched organosilicon;

[0040] Step A2, 34.5g of methacryloyl chloride and 30mL of benzene were mixed uniformly, recorded as solution A, 9g of 2-(aminomethyl)-1,3-propanediol and 30g of triethylamine were added to a reactor containing 200mL of toluene and stirred and mixed uniformly, 30mL of solution A was slowly dripped into the reactor under ice-water bath and stirring conditions using a constant pressure dropping funnel, the dropping time was 3.5h, after the dropwise addition was completed, the reaction was carried out at room temperature for 12h, after the reaction was completed, the filtrate was collected, washed, and dried, and then the filtrate was filtered again, the filtrate was collected, and the intermediate product 1 was obtained by distillation under reduced pressure;

[0041] Step A3, add 20.3g of intermediate product 1 and 1.1g of potassium hydroxide into a reactor, introduce nitrogen for 10min, and heat to 100°C under nitrogen for 3.5h. After cooling to room temperature, add 30g of propylene oxide, stir and heat to 65°C for 4h, then lower the system temperature to 25°C, add 12g of ethylene oxide, stir and heat to 65°C for 4.5h. After the reaction is completed, a terminal double-bond polyether is obtained;

[0042] Step A4, add 15g of hydrogen-terminated hyperbranched silicone and 0.65g of chloroplatinic acid into the reactor, introduce nitrogen for 10min, and heat to 85°C under nitrogen conditions, and use a constant pressure dropping funnel to drop 20g of double-bond-terminated polyether for 1.5h. After the addition is completed, continue the reaction for 3h, turn off the nitrogen, and distill under reduced pressure to obtain polyether-modified silicone oil.

[0043] 2) The modified mesoporous silica is prepared by the following steps:

[0044] Step B1, 0.75g of hexadecyltrimethylammonium bromide was stirred and mixed in 60mL of deionized water, 5g of 0.1mol / L hydrochloric acid was added and stirred for 30min, and then 4mL of ethyl orthosilicate and 0.3mL of γ-aminopropyltriethoxysilane were added and stirred and mixed, and after standing for 2h, the mixture was heated to 70°C and stirred for 10h. After the reaction was completed, the mixture was centrifuged, washed and dried, and the obtained product was dispersed in a mixture of 20mL of ethanolamine and 80mL of ethanol, and refluxed and extracted at 90°C for 12h, and then centrifuged, washed and dried, and then the extraction was repeated once to obtain mesoporous silica;

[0045] Step B2, add 0.75g of mesoporous silica to a reactor containing 50mL of deionized water, ultrasonically treat for 30min, adjust the pH of the mixed solution to 8.5, add 0.2g of 2H,2H-perfluorooctanoic acid and ultrasonically treat for 30min, then react under nitrogen for 10h at a reaction temperature of 80°C. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to obtain modified mesoporous silica.

[0046] Example 3

[0047] 1) The polyether-modified silicone is prepared by the following steps:

[0048] Step A1, 0.1g of tris(pentafluorophenyl)borane was stirred and mixed in a reactor containing 500mL of cyclohexane, and then 10.4g of ethyl orthosilicate and 33.6g of dimethyldimethoxysilane were slowly added dropwise to the above reactor under stirring for 2.5h, and then 24g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise for 60min. After the addition was completed, 3g of activated carbon and 2.5mL of triethylamine were added to the mixture and stirred for 5min. The mixture was filtered, rotary evaporated, concentrated, dried and fractionated under reduced pressure to obtain terminal hydrogen hyperbranched organosilicon;

[0049] Step A2, 46g of methacryloyl chloride and 40mL of benzene were mixed uniformly, recorded as solution A, 12g of 2-(aminomethyl)-1,3-propanediol and 40g of triethylamine were added to a reactor containing 200mL of toluene and stirred to mix uniformly, 40mL of solution A was slowly dripped into the reactor under ice-water bath and stirring conditions using a constant pressure dropping funnel, the dropping time was 4h, after the dropwise addition was completed, the reaction was carried out at room temperature for 12h, after the reaction was completed, the filtrate was collected, washed and dried, and then the filtrate was filtered again, the filtrate was collected, and the intermediate product 1 was obtained by distillation under reduced pressure;

[0050] Step A3, add 27g of intermediate product 1 and 1.5g of potassium hydroxide into a reactor, introduce nitrogen for 10min, heat to 120°C under nitrogen for 5h, cool to room temperature, add 40g of propylene oxide, stir and heat to 80°C for 6h, then lower the system temperature to 35°C, add 16g of ethylene oxide, stir and heat to 80°C for 6h, and after the reaction is completed, obtain a terminal double-bond polyether;

[0051] Step A4, add 20g of hydrogen-terminated hyperbranched silicone and 0.8g of chloroplatinic acid into the reactor, introduce nitrogen for 10min, and heat to 95°C under nitrogen conditions, and use a constant pressure dropping funnel to drop 25g of double-bond-terminated polyether for 2h. After the addition is completed, continue the reaction for 4h, turn off the nitrogen, and distill under reduced pressure to obtain polyether-modified silicone oil.

[0052] 2) The modified mesoporous silica is prepared by the following steps:

[0053] Step B1, 0.9 g of hexadecyltrimethylammonium bromide was stirred and mixed in 60 mL of deionized water, 6 g of 0.1 mol / L hydrochloric acid was added and stirred for 30 min, and then 4.5 mL of ethyl orthosilicate and 0.4 mL of γ-aminopropyltriethoxysilane were added and stirred and mixed, and after standing for 2 h, the mixture was heated to 80 ° C and stirred for 12 h. After the reaction was completed, the mixture was centrifuged, washed and dried, and the obtained product was dispersed in a mixed solution of 20 mL of ethanolamine and 80 mL of ethanol, and refluxed and extracted at 90 ° C for 12 h. After centrifugation, washing and drying, the extraction was repeated once to obtain mesoporous silica;

[0054] Step B2, add 1g of mesoporous silica to a reactor containing 50mL of deionized water, ultrasonically treat for 30min, adjust the pH of the mixed solution to 8.5, add 0.3g of 2H,2H-perfluorooctanoic acid and ultrasonically treat for 30min, then react under nitrogen for 12h at a reaction temperature of 90°C. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to obtain modified mesoporous silica.

[0055] Example 4

[0056] A method for preparing a polyether-modified silicone defoamer comprises the following steps:

[0057] 10 parts of the polyether-modified silicone prepared in Example 1, 20 parts of dimethyl silicone oil, 2 parts of the modified mesoporous silica prepared in Example 1, 2 parts of polyvinyl alcohol, 6 parts of Span 80, and 35 parts of deionized water;

[0058] The raw materials were weighed according to weight proportions, and the polyether-modified silicone prepared in Example 1, dimethyl silicone oil, modified mesoporous silica prepared in Example 1 and polyvinyl alcohol were mixed and stirred evenly, and the temperature was raised to 100° C. and stirring was continued for 30 min. Span 80 and deionized water were added and stirred for 5 min to obtain a polyether-modified silicone defoamer.

[0059] Example 5

[0060] A method for preparing a polyether-modified silicone defoamer comprises the following steps:

[0061] 20 parts of the polyether-modified silicone prepared in Example 2, 30 parts of dimethyl silicone oil, 3 parts of the modified mesoporous silica prepared in Example 2, 3 parts of polyvinyl alcohol, 808 parts of Span, and 45 parts of deionized water;

[0062] The raw materials were weighed according to their weight proportions, and the polyether-modified silicone prepared in Example 2, dimethyl silicone oil, modified mesoporous silica prepared in Example 2 and polyvinyl alcohol were mixed and stirred evenly, and the temperature was raised to 140° C. and stirring was continued for 30 min. Span 80 and deionized water were added and stirred for 10 min to obtain a polyether-modified silicone defoamer.

[0063] Example 6

[0064] A method for preparing a polyether-modified silicone defoamer comprises the following steps:

[0065] 30 parts of the polyether-modified silicone prepared in Example 3, 40 parts of dimethyl silicone oil, 5 parts of the modified mesoporous silica prepared in Example 3, 4 parts of polyvinyl alcohol, 10 parts of Span 80, and 55 parts of deionized water;

[0066] The raw materials were weighed according to their weight proportions, and the polyether-modified silicone prepared in Example 3, dimethyl silicone oil, modified mesoporous silica prepared in Example 3 and polyvinyl alcohol were mixed and stirred evenly, and the temperature was raised to 160° C. and stirring was continued for 30 min. Span 80 and deionized water were added and stirred for 10 min to obtain a polyether-modified silicone defoamer.

[0067] Comparative Example 1

[0068] This comparative example is a defoaming agent, which differs from Example 6 in that an equal amount of hydrogen-containing silicone oil is used to replace the hydrogen-terminated hyperbranched silicone in the polyether-modified silicone prepared in Example 3, and the rest are the same.

[0069] Comparative Example 2

[0070] This comparative example is a defoaming agent, which differs from Example 6 in that the modified mesoporous silica prepared in Example 3 is not added, and the rest is the same.

[0071] The defoamers prepared in Examples 4-6 and Comparative Examples 1-2 were tested for foam suppression, defoaming properties and compatibility:

[0072] Take 6 parts of the same acrylic varnish coating system, add 0.3% of the defoamer of Examples 4-6 and Comparative Examples 1-2 respectively, then place them on a vibrator and vibrate for 30 minutes, record the foam suppression time and defoaming time; then mix the defoamer of Examples 4-6 and Comparative Examples 1-2 with the aqueous system and the oily system respectively, and observe after shaking; the test results are shown in the following table:

[0073]

[0074] After the polyether-modified organic silicon defoamer of the present invention is added into the coating, it has a relatively long antifoaming time of 30min-35min and a relatively short defoaming time of 5-8min, indicating that the defoamer has excellent antifoaming and defoaming performances and good compatibility and stability.

[0075] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A polyether-modified silicone defoamer, characterized in that: The raw materials include the following mass fractions: 10-30 parts of polyether modified silicone, 20-40 parts of dimethyl silicone oil, 2-5 parts of modified mesoporous silica, 2-4 parts of thickener, 6-10 parts of emulsifier, and 35-55 parts of deionized water; The polyether-modified silicone is prepared by the following steps: Step A1, tri(pentafluorophenyl)borane is stirred and mixed in a reactor containing cyclohexane, and then ethyl orthosilicate and dimethyldimethoxysilane are slowly added dropwise to the reactor under stirring for 1.5-2.5 hours, and then 1,1,3,3-tetramethyldisiloxane is slowly added dropwise for 40-60 minutes. After the addition is completed, activated carbon and triethylamine are added to the mixture and stirred for 5 minutes. The mixture is filtered, rotary evaporated, concentrated, dried and fractionated under reduced pressure to obtain terminal hydrogen hyperbranched organosilicon; Step A2, methacryloyl chloride and toluene are mixed uniformly, recorded as solution A, 2-(aminomethyl)-1,3-propanediol and triethylamine are added to the reactor containing toluene, stirred and mixed uniformly, and solution A is slowly dripped into the reactor under ice-water bath and stirring conditions using a constant pressure dropping funnel. The dropping time is 3-4 hours. After the dropwise addition is completed, the reaction is carried out at room temperature for 12 hours. After the reaction is completed, the filtrate is filtered, collected, washed, and dried, and then filtered again, the filtrate is collected, and distilled under reduced pressure to obtain intermediate product 1; Step A3, add the intermediate product 1 and potassium hydroxide into a reaction kettle, introduce nitrogen for 10 minutes, heat to 80-120°C under nitrogen conditions for reaction for 2-5 hours, cool to room temperature, add propylene oxide, stir and heat to 50-80°C for reaction for 3-6 hours, then lower the system temperature to 10-35°C, add ethylene oxide, stir and heat to 50-80°C for reaction for 3-6 hours, and after the reaction is completed, obtain a terminal double-bond polyether; Step A4, add hydrogen-terminated hyperbranched organosilicon and chloroplatinic acid into a reactor, introduce nitrogen for 10 minutes, and heat to 75-95°C under nitrogen conditions, and use a constant pressure dropping funnel to dropwise add the double-bond polyether for 1-2 hours. After the addition is completed, continue the reaction for 2-4 hours, turn off the nitrogen, and distill under reduced pressure to obtain polyether-modified silicone oil.

2. A polyether-modified silicone defoamer according to claim 1, characterized in that: In step A1, the usage ratio of tri(pentafluorophenyl)borane, cyclohexane, ethyl orthosilicate, dimethyldimethoxysilane, 1,1,3,3-tetramethyldisiloxane, activated carbon and triethylamine is 0.05-0.1 g:500 mL:5.2-10.4 g:14.4-33.6 g:12-24 g:2-3 g:1.5-2.5 mL.

3. The polyether-modified silicone defoamer according to claim 1, characterized in that: In step A2, the usage ratio of 2-(aminomethyl)-1,3-propanediol, triethylamine, toluene and solution A is 6-12 g:20-40 g:200 mL:20-40 mL, and the usage ratio of methacryloyl chloride and toluene in solution A is 23-46 g:20-40 mL.

4. The polyether-modified silicone defoamer according to claim 1, characterized in that: In step A3, the usage ratio of the intermediate product 1, potassium hydroxide, propylene oxide and ethylene oxide is 13.5-27 g: 0.7-1.5 g: 20-40 g: 8-16 g.

5. The polyether-modified silicone defoamer according to claim 1, characterized in that: In step A4, the usage ratio of the terminal hydrogen hyperbranched silicone, the terminal double bond polyether and chloroplatinic acid is 10-20 g: 15-25 g: 0.5-0.8 g.

6. The polyether-modified silicone defoamer according to claim 1, characterized in that: The modified mesoporous silica is prepared by the following steps: Step B1, stir and mix hexadecyltrimethylammonium bromide in deionized water, add 0.1 mol / L hydrochloric acid and stir for 30 minutes, then add ethyl orthosilicate and γ-aminopropyltriethoxysilane and stir and mix evenly, let stand for 2 hours, heat to 60-80°C and stir for 8-12 hours, after the reaction is completed, centrifuge, wash and dry, and then disperse the obtained product in a mixed solution of 20 mL of ethanolamine and 80 mL of ethanol, reflux extract at 90°C for 12 hours, centrifuge, wash and dry, and then repeat the extraction once to obtain mesoporous silica; Step B2, add mesoporous silica to a reactor containing deionized water, ultrasonically treat for 30 minutes, adjust the pH of the mixed solution to 8.5, add 2H, 2H-perfluorooctanoic acid and ultrasonically treat for 30 minutes, then react under nitrogen conditions for 8-12 hours at a reaction temperature of 70-90°C. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to obtain modified mesoporous silica.

7. The polyether-modified silicone defoamer according to claim 6, characterized in that: In step B1, the usage ratio of hexadecyltrimethylammonium bromide, deionized water, hydrochloric acid, ethyl orthosilicate and γ-aminopropyltriethoxysilane is 0.6-0.9 g: 60 mL: 4-6 g: 3-4.5 mL: 0.2-0.4 mL.

8. The polyether-modified silicone defoamer according to claim 6, characterized in that: In step B2, the usage ratio of mesoporous silica, 2H,2H-perfluorooctanoic acid and deionized water is 0.5-1 g: 0.1-0.3 g: 50 mL.

9. The method for preparing a polyether-modified silicone defoamer according to claim 1, characterized in that: The following steps are involved: Weigh the raw materials by weight, mix and stir the polyether-modified silicone, dimethyl silicone oil, modified mesoporous silica and thickener evenly, raise the temperature to 100-160°C, continue stirring for 30 minutes, then add the emulsifier and deionized water and stir for 5-10 minutes to obtain the polyether-modified silicone defoamer.

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