Synthesis of a defoamer having excellent defoaming properties

Abstract

The application discloses synthesis of a defoaming agent with excellent defoaming performance, and relates to the field of defoaming agents. The defoaming agent with excellent defoaming performance comprises 23-35 parts of polyether, 12-20 parts of modified nano silicon dioxide, 5-15 parts of a composite emulsifier, 5-13 parts of hydrophobic particles and 25-35 parts of a solvent. The polyether comprises a fatty alcohol modified polyether and an organic silane modified polyether, and the weight ratio of the two is 1:(1.3-2.5). Through synergistic effect of the two, the problem of weak defoaming performance and low foam inhibition capacity when the two are used alone can be solved. The composite emulsifier comprises a fatty acid sucrose ester, a polyethylene glycol bislaurate and Tween 80, and the weight ratio of the three is 1:(1.3-1.5):(1.5-1.9). The defoaming agent has good dispersibility and storage stability. The defoaming agent provided by the application has the effects of strong defoaming performance, rapid bubble breaking and long foam inhibition time.

Description

Technical Field

[0001] This application relates to the field of defoamers, and in particular to the synthesis of a defoamer with excellent defoaming properties. Background Technology

[0002] Industrial production often generates a large amount of foam, which can cause the internal liquid level of equipment to be artificially high, resulting in wasted internal space and reduced production capacity. If foam is not controlled in time, it can easily cause overflow in production equipment, affecting production process control and equipment operation, leading to waste of raw materials, and in severe cases, affecting product quality and corroding production equipment. Defoamers are chemical substances that can eliminate or inhibit foam by adding a small amount to a foaming system. They have the advantages of fast defoaming speed, small dosage, and low economic cost. Currently, common defoamers are mainly divided into two categories: non-silicone defoamers and silicone defoamers. Common non-silicone defoamers use mineral oil, polyether, amide, or fatty alcohol as active ingredients, while silicone defoamers use polysiloxanes as active ingredients.

[0003] For related technologies, please refer to Chinese invention patent application with publication number CN115197411A, which discloses a long fatty chain modified polyether, a polyether defoamer composition and preparation method. The long fatty chain modified polyether is composed of 10-47% long-chain fatty alcohol, 5-10% ethylene oxide, 30-60% propylene oxide, 10-30% butyl oxide, and 50-200ppm bimetallic catalyst. It has good spreadability on the foam surface and good penetration ability into the foam, and can effectively suppress foam.

[0004] Regarding the aforementioned technologies, the inventors believe that there are still shortcomings: non-silicone defoamers with polyether or fatty alcohol as the main active ingredient have weak defoaming and foam-suppressing performance in systems rich in anionic surfactants, and their ability to suppress foam still cannot meet the needs of industrial production. Therefore, there is an urgent need for a new type of defoamer to improve the defoaming performance of defoamers. Summary of the Invention

[0005] In order to improve the defoaming properties of defoamers, this application provides a method for synthesizing a defoamer with excellent defoaming performance.

[0006] This application provides a defoamer with excellent defoaming properties, employing the following technical solution: An antifoaming agent with excellent defoaming properties comprises: 23-35 parts of composite polyether, 12-20 parts of modified nano silica, 5-15 parts of composite emulsifier, 5-13 parts of hydrophobic particles, and 25-35 parts of solvent; wherein the composite polyether comprises fatty alcohol modified polyether and organosilane modified polyether, with a weight ratio of 1:(1.3-2.5).

[0007] By adopting the above technical solution, using composite polyether fatty alcohol modified polyether and organosilane modified polyether, a synergistic effect is achieved, which can solve the problems of weak defoaming and low foam suppression ability of defoamers. Fatty alcohol modified polyether has both emulsifying and defoaming functions, while organosilane modified polyether is a polymer compound containing both polyether segments and polysiloxane segments. Due to the hydrophilicity of the polyether segments, organosilane modified polyether can be miscible with water, while the polysiloxane segments are hydrophobic. Therefore, organosilane modified polyether is a high-performance surfactant. Through the emulsifying function of fatty alcohol polyether, organosilane modified polyether can be dispersed into fine particles, which is beneficial for the polyether to spread on the foam surface, better inhibiting foam formation or breaking up foam, thereby improving the defoaming and foam suppression ability of the defoamer.

[0008] Preferably, the fatty alcohol modified polyether mainly comprises the following components: 30-40 parts ethylene oxide, 60-70 parts propylene oxide, 15-25 parts cetyl alcohol, and 3-5 parts catalyst.

[0009] By adopting the above technical solution, cetyl alcohol is used to modify polyether. Cetyl alcohol is used as the initiator, and ethylene oxide and propylene oxide are introduced. Fatty alcohol modified polyether is synthesized under the action of a catalyst. The orderly arrangement of ethylene oxide and propylene oxide forms a block structure, which improves the permeability of fatty alcohol modified polyether and makes fatty alcohol modified polyether have a better foam control effect.

[0010] Preferably, the organosilane-modified polyether mainly comprises the following components: 10-20 parts of polydimethylsiloxane, 35-47 parts of ethylene oxide, 53-65 parts of propylene oxide, and 5-7 parts of catalyst.

[0011] By adopting the above technical solution, polydimethylsiloxane is used to modify polyether. The polyether segments are hydrophilic, so the organosilane-modified polyether can be miscible with water. At the same time, the polydimethylsiloxane segments are hydrophobic, so the resulting polyether-modified silicone oil is a type of surfactant with excellent performance.

[0012] Preferably, the modified nano-silica mainly comprises the following components: 25-37 parts nano-silica, 3-5 parts... Hexadecyl alcohol.

[0013] By adopting the above technical solution and modifying nano-silica with hexadecyl alcohol, the size of nano-silica particles can be reduced and the specific surface area increased. The modified nano-silica has a large number of surface atoms, and the surface energy and surface tension increase sharply with the decrease of particle size. In addition, there are a large number of active hydroxyl groups on the surface of nano-silica, which have chemical reactivity and strong hydrophilicity. Combining modified nano-silica with polyether has a significant synergistic effect, which makes the two more compatible and enhances their defoaming performance.

[0014] Preferably, the composite emulsifier comprises fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:(1.3-1.5):(1.5-1.9).

[0015] By adopting the above technical solution, the stability of defoamers can be improved by using composite emulsifiers. Since the amount of emulsifier affects the size of the emulsion particles, and thus the stability of the emulsion, when the amount of emulsifier is too small, the emulsifier cannot completely coat the surface of the latex particles, and therefore cannot form a complete oil-in-water system. However, when the amount of emulsifier is too large, the particle size is too small and the interfacial energy is too large, which leads to a decrease in the stability of the emulsion. Therefore, by compounding fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80, the defoamer can have good dispersibility and stability. Under these emulsification conditions, it is more conducive to improving the defoaming and foam-suppressing abilities of the defoamer.

[0016] This application also provides a method for synthesizing a defoamer with excellent defoaming properties, using the following technical solution: The synthesis of a defoamer with excellent defoaming properties includes the following steps: S1. Weigh the fatty alcohol modified polyether and organosilane modified polyether at a weight ratio of 1:(1.3-2.5), add 25-35 parts of solvent and mix evenly to obtain solution A; S2. Mix 12-20 parts of modified nano-silica, 5-15 parts of composite emulsifier, and 5-13 parts of hydrophobic particles evenly, add solution A and continue stirring evenly to obtain the defoamer.

[0017] By adopting the above technical solutions, the synergistic effect of polyethers, including fatty alcohol-modified polyethers and organosilane-modified polyethers, can solve the problems of weak defoaming and low foam suppression ability of defoamers. At the same time, the introduction of solvents makes the copolymerization reaction more uniform and improves the spreading and dispersion speed of the defoamer composition in the foaming system, thereby improving its defoaming and foam suppression properties. The introduction of hydrophobic particles increases the defoaming rate of the defoamer composition, thereby improving its instantaneous defoaming performance. Combined with modified nano-silica, it has a significant synergistic effect with polyethers, enhancing the defoaming performance of both. By compounding fatty acid sucrose esters, polyethylene glycol dilaurate, and Tween 80, the stability of the emulsion can be improved. Under these emulsification conditions, the defoaming, foam suppression, and stability of the defoamer are improved.

[0018] Preferably, the method for preparing the organosilane-modified polyether includes the following steps: Mix 10-20 parts of polydimethylsiloxane and 5-7 parts of catalyst evenly, purge with nitrogen, heat to remove moisture, add 35-47 parts of ethylene oxide and 53-65 parts of propylene oxide, react at 100-120℃ for 2-3 hours, stop heating, cool to room temperature, and obtain organosilane modified polyether.

[0019] By adopting the above technical solution, polydimethylsiloxane is used to modify polyether. The polyether segments are hydrophilic, so the organosilane-modified polyether can be miscible with water. At the same time, the polydimethylsiloxane segments are hydrophobic, so the resulting polyether-modified silicone oil is a type of surfactant with excellent performance.

[0020] Preferably, the preparation method of the fatty alcohol modified polyether includes the following steps: Mix 15-25 parts of cetyl alcohol and 3-5 parts of catalyst evenly, purge with nitrogen, evacuate, and remove moisture. React at a reaction pressure of 0.01-0.1 MPa and a reaction temperature of 110-130℃ for 3-6 hours. Then, continue to raise the temperature to 140-170℃, add 30-40 parts of ethylene oxide and 60-70 parts of propylene oxide, and continue to react for 1-2 hours. After cooling to room temperature, fatty alcohol modified polyether is obtained.

[0021] By adopting the above technical solution, cetyl alcohol is used to modify polyether. Cetyl alcohol is used as the initiator, and ethylene oxide and propylene oxide are introduced. Fatty alcohol modified polyether is synthesized under the action of a catalyst. The orderly arrangement of ethylene oxide and propylene oxide forms a block structure, which improves the permeability of fatty alcohol modified polyether and makes fatty alcohol modified polyether have a better foam control effect.

[0022] Preferably, the method for preparing the modified nano-silica includes the following steps: 25-37 parts of nano-silica were mixed with 3-5 parts of cetyl alcohol and reacted at a reaction pressure of 0.1-0.5 MPa and a reaction temperature of 180-260℃ for 3-5 hours. After the reaction was completed, the nano-silica was dried to obtain the modified nano-silica.

[0023] By adopting the above technical solution and modifying nano-silica with hexadecyl alcohol, the size of nano-silica particles can be reduced, the specific surface area can be increased, the number of surface atoms of the modified nano-silica is increased, the surface energy and surface tension increase sharply with the decrease of particle size, and the defoaming performance of nano-silica is enhanced.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. By adopting the above technical solution, using composite polyether fatty alcohol modified polyether and organosilane modified polyether, a synergistic effect can be achieved, solving the problems of weak defoaming and low foam suppression ability of defoamers. Fatty alcohol polyether has both emulsifying and defoaming functions, while organosilane modified polyether is a polymer compound containing both polyether and polysiloxane segments. Due to the hydrophilicity of the polyether segments, organosilane modified polyether is miscible with water, while the hydrophobicity of the polysiloxane segments makes it a high-performance surfactant. The emulsifying function of fatty alcohol polyether can disperse organosilane modified polyether into fine particles, which is beneficial for the polyether to spread on the foam surface, better inhibiting foam formation or breaking up foam, thereby improving the defoaming and foam suppression ability of the defoamer. 2. By adopting the above technical solution, the size of nano-silica can be reduced and the specific surface area increased by modifying it with hexadecyl alcohol. The modified nano-silica has a large number of surface atoms, and the surface energy and surface tension increase sharply with the decrease of particle size. In addition, there are a large number of active hydroxyl groups on the surface of nano-silica, which have chemical reactivity and strong hydrophilicity. Combining modified nano-silica with polyether has a significant synergistic effect, which makes the two more compatible and enhances their defoaming performance. 3. By adopting the above technical solution, the stability of the defoamer can be improved by using a composite emulsifier. Since the amount of emulsifier affects the size of the emulsion particles, and thus the stability of the emulsion, when the amount of emulsifier is too small, the emulsifier cannot completely coat the surface of the latex particles, and therefore cannot form a complete oil-in-water system. However, when the amount of emulsifier is too large, the particle size is too small and the interfacial energy is too large, which leads to a decrease in the stability of the emulsion. Therefore, by compounding fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80, the defoamer can have good dispersibility and stability. Under these emulsification conditions, it is more conducive to improving the defoaming and foam-suppressing ability of the defoamer. Detailed Implementation

[0025] The present application will be further described in detail below with reference to the embodiments.

[0026] Preparation Example I: Preparation of Fatty Alcohol Modified Polyether Preparation Example I-1 15g of cetyl alcohol and 3g of catalyst were mixed and stirred for 15min. Nitrogen gas was introduced, and the reactor was evacuated to a vacuum state. The mixture was dehydrated for 40min, and then reacted at a reaction pressure of 0.01MPa and a reaction temperature of 110℃ for 3h. The temperature was then increased to 140℃, and 30g of ethylene oxide and 70g of propylene oxide were added. The reaction was continued for 1h. After cooling to 25℃, fatty alcohol modified polyether was obtained. The catalyst used in this preparation example was a platinum-isopropanol catalyst with a mass fraction of 0.01%.

[0027] Preparation Example I-2 20g of cetyl alcohol and 4g of catalyst were mixed and stirred for 20min. Nitrogen gas was introduced, and the reactor was evacuated to a vacuum state. Dehydration was carried out for 45min. Then, the reaction was carried out at a reaction pressure of 0.05MPa and a reaction temperature of 120℃ for 4.5h. The temperature was then increased to 155℃, and 35g of ethylene oxide and 65g of propylene oxide were added. The reaction was continued for 1.5h. After cooling to 25℃, fatty alcohol modified polyether was obtained. The catalyst used in this preparation example was a platinum-isopropanol catalyst with a mass fraction of 0.01%.

[0028] Preparation Example I-3 25g of cetyl alcohol and 5g of catalyst were mixed and stirred for 25min. Nitrogen gas was introduced, and the reactor was evacuated to a vacuum state. Dehydration was carried out for 50min. Then, the reaction was carried out at a reaction pressure of 0.1MPa and a reaction temperature of 130℃ for 6h. The temperature was then increased to 170℃, and 40g of ethylene oxide and 60g of propylene oxide were added. The reaction was continued for 2h. After cooling to 25℃, fatty alcohol modified polyether was obtained. The catalyst used in this preparation example was a platinum-isopropanol catalyst with a mass fraction of 0.01%.

[0029] Preparation Example II: Preparation of Organosilanes Modified Polyethers Preparation Example II-1 10g of polydimethylsiloxane and 5g of catalyst were mixed and stirred for 30min. Nitrogen gas was introduced and the mixture was heated to 100℃ and dehydrated for 60min. 35g of ethylene oxide and 65g of propylene oxide were added and reacted at 100℃ for 2h. Heating was stopped and the mixture was cooled to 25℃ to obtain organosilane modified polyether. The catalyst used in this preparation example was a platinum-isopropanol catalyst with a mass fraction of 0.01%.

[0030] Preparation Example II-2 15g of polydimethylsiloxane and 6g of catalyst were mixed and stirred for 40 min. Nitrogen gas was introduced and the mixture was heated to 110°C for 65 min to remove water. Then, 41g of ethylene oxide and 59g of propylene oxide were added, and the mixture was reacted at 110°C for 2.5 h. Heating was then stopped, and the mixture was cooled to 25°C to obtain organosilane-modified polyether. The catalyst used in this preparation example was a platinum-isopropanol catalyst with a mass fraction of 0.01%.

[0031] Preparation Example II-3 20g of polydimethylsiloxane and 7g of catalyst were mixed and stirred for 50min. Nitrogen gas was introduced and the mixture was heated to 120℃ for 70min to remove water. Then, 47g of ethylene oxide and 53g of propylene oxide were added and reacted at 120℃ for 3h. Heating was stopped and the mixture was cooled to 25℃ to obtain organosilane-modified polyether. The catalyst used in this preparation example was a platinum-isopropanol catalyst with a mass fraction of 0.01%.

[0032] Preparation Example III: Preparation of Modified Nano-Silica Preparation Example III-1 25g of nano-silica was mixed with 3g of cetyl alcohol and reacted for 3h at a reaction pressure of 0.1MPa and a reaction temperature of 180℃. After the reaction was completed, the mixture was dried at 100℃ for 2h to obtain modified nano-silica.

[0033] Preparation Example III-2 31g of nano-silica was mixed with 4g of cetyl alcohol and reacted for 4h at a reaction pressure of 0.3MPa and a reaction temperature of 240℃. After the reaction was completed, it was dried at 110℃ for 2.5h to obtain modified nano-silica.

[0034] Preparation Example III-3 37g of nano-silica was mixed with 5g of cetyl alcohol and reacted for 5h at a reaction pressure of 0.5MPa and a reaction temperature of 260℃. After the reaction was completed, it was dried at 120℃ for 3h to obtain modified nano-silica. Example

[0035] Example 1 S1. Weigh 10g of the fatty alcohol modified polyether obtained in Preparation Example I-1 and 13g of the organosilane modified polyether obtained in Preparation Example II-1, add 25g of solvent and mix. Stir at 70°C and 2000rpm for 1.5h to obtain solution A. The solvent used in this example is fatty alcohol polyoxyethylene ether. S2. Mix 12g of the modified nano-silica obtained in Preparation Example III-1, 5g of the composite emulsifier, and 5g of hydrophobic particles. Stir at 220°C and 4000rpm for 2 hours. Add solution A obtained in S1 and continue stirring at 220°C and 4000rpm for 3 hours. Cool to 25°C to obtain the defoamer. The composite emulsifier used in this example includes fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:1.3:1.5. The hydrophobic particles used are silica.

[0036] Example 2 S1. Weigh 10g of the fatty alcohol modified polyether obtained in Preparation Example I-1 and 13g of the organosilane modified polyether obtained in Preparation Example II-1, add 30g of solvent and mix. Stir at 75°C and 2500rpm for 1.5h to obtain solution A. The solvent used in this example is fatty alcohol polyoxyethylene ether. S2. Mix 16g of the modified nano-silica obtained in Preparation Example III-1, 10g of the composite emulsifier, and 8g of hydrophobic particles. Stir at 230℃ and 4500rpm for 2.5h. Add solution A obtained in S1 and continue stirring at 230℃ and 4500rpm for 3.5h. Cool to 25℃ to obtain the defoamer. The composite emulsifier used in this example includes fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:1.3:1.5. The hydrophobic particles used are silica.

[0037] Example 3 S1. Weigh 10g of the fatty alcohol modified polyether obtained in Preparation Example I-1 and 13g of the organosilane modified polyether obtained in Preparation Example II-1, add 35g of solvent and mix. Stir at 80°C and 3000rpm for 1.5h to obtain solution A. The solvent used in this example is fatty alcohol polyoxyethylene ether. S2. Mix 20g of the modified nano-silica obtained in Preparation Example III-1, 15g of the composite emulsifier, and 13g of hydrophobic particles. Stir at 240℃ and 5000rpm for 3h. Add solution A obtained in S1. Continue stirring at 240℃ and 5000rpm for 4h. Cool to 25℃ to obtain the defoamer. The composite emulsifier used in this example includes fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:1.3:1.5. The hydrophobic particles used are silica.

[0038] Example 4 The difference between Example 4 and Example 1 is that the mass of the fatty alcohol modified polyether used in Example 4 is 10g and the mass of the organosilane modified polyether is 19g.

[0039] Example 5 The difference between Example 5 and Example 1 is that the mass of the fatty alcohol modified polyether used in Example 5 is 10g and the mass of the organosilane modified polyether is 25g.

[0040] Example 6 The difference between Example 6 and Example 1 is that the composite emulsifier used in Example 6 includes fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:1.4:1.7.

[0041] Example 7 The difference between Example 7 and Example 1 is that the composite emulsifier used in Example 7 includes fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:1.5:1.9.

[0042] Example 8 The difference between Example 8 and Example 1 is that the fatty alcohol modified polyether used in Example 8 is derived from Preparation Example I-2.

[0043] Example 9 The difference between Example 9 and Example 1 is that the fatty alcohol modified polyether used in Example 9 is derived from Preparation Example I-3.

[0044] Example 10 The difference between Example 10 and Example 1 is that the organosilane-modified polyether used in Example 10 is derived from Preparation Example II-2.

[0045] Example 11 The difference between Example 11 and Example 1 is that the organosilane-modified polyether used in Example 11 is derived from Preparation Example II-3.

[0046] Example 12 The difference between Example 12 and Example 1 is that the modified nano-silica used in Example 12 is derived from Preparation Example III-2.

[0047] Example 13 The difference between Example 13 and Example 1 is that the modified nano-silica used in Example 13 is derived from Preparation Example III-3.

[0048] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the polyether used in Comparative Example 1 is 23g of fatty alcohol modified polyether, which comes from Preparation Example I-1.

[0049] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the polyether used in Comparative Example 2 is 23g of organosilane modified polyether, which is derived from Preparation Example II-1.

[0050] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the mass of the fatty alcohol modified polyether used in Comparative Example 3 is 10g and the mass of the organosilane modified polyether is 8g.

[0051] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the mass of the fatty alcohol modified polyether used in Comparative Example 4 is 10g and the mass of the organosilane modified polyether is 30g.

[0052] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the composite emulsifier used in Comparative Example 5 includes fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:1.1:1.2.

[0053] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the composite emulsifier used in Comparative Example 6 includes fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:1.8:2.1.

[0054] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that Comparative Example 7 uses unmodified ordinary nano-silica.

[0055] Performance testing 1. Add 600 mL of a 1% sodium dodecylbenzenesulfonate aqueous solution to a circulating bubbler with a volume of 1000 mL and an inner diameter of 5 cm, until the liquid level reaches the lowest mark "0 mL". Then set the temperature to 80 °C, the flow rate to 6 L / min, and the voltage to 220 V. Turn on the temperature control switch to heat the sodium dodecylbenzenesulfonate aqueous solution to the set temperature and then turn on the circulating pump to start agitation and foaming. When the foam rises to 350 mL, add 0.2 mL of the defoamer obtained in Examples 1-13 and Comparative Examples 1-7. Record the lowest mark reached by the foam height and the time taken, T1, which is the defoaming time of the defoamer. The time taken for the foam to reach 350 mL again is recorded as T2, which is the foam suppression time of the defoamer.

[0056] The specific test results are as follows: As shown in Table 1, the defoamer provided in this application consumes less time when the foam reaches the lowest mark, and the lowest mark can be as low as 115ml, indicating that the defoamer provided in this application has strong defoaming properties; and the defoamer provided in this application takes a longer time to reach 350mL again, indicating that the defoamer provided in this application also has strong foam suppression properties.

[0057] As can be seen from the test results of Examples 1-3, the process parameters for preparing defoamers provided in this application are all beneficial to improving the defoaming and foam-suppressing abilities of defoamers, and the changes within the parameter range have little effect on the defoaming time and foam-suppressing time of defoamers.

[0058] The test results of Examples 1, 4, 5 and Comparative Examples 3, 4 show that when the mass ratio of the mixed modified polyether (fatty alcohol modified polyether and organosilane modified polyether) used in this application varies within the range of 1:(1.1-1.7), it is beneficial to improve the defoaming and foam-suppressing abilities of the defoamer, and has little effect on the defoaming time and foam-suppressing time. However, when the mass ratio of fatty alcohol modified polyether to organosilane modified polyether is lower or higher than this range, the time it takes for the defoamer to reach the minimum scale increases, the minimum scale reached by the foam increases, and the time it takes for the foam to reach 350 mL again is shortened. The test results of Comparative Examples 1, 2 show that when only fatty alcohol modified polyether or organosilane modified polyether is used, the defoaming time and the minimum foam scale of the obtained defoamer both increase, indicating poor defoaming performance, and the foam-suppressing time is also low, indicating poor foam-suppressing performance.

[0059] The test results from Examples 1, 6, 7 and Comparative Examples 5, 6 show that when the mass ratio of the composite emulsifiers used in this application—fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80—is within the range of 1:(1.3-1.5):(1.5-1.9), it is beneficial to improve the defoaming and foam-suppressing abilities of the defoamer, and has little effect on the defoaming and foam-suppressing time of the defoamer. However, when the mass ratio of fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 is lower than or exceeds this range, the time it takes for the defoamer to reach the minimum scale becomes longer, the minimum scale reached by the foam becomes larger, and the time it takes for the foam to reach 350 mL again is shortened.

[0060] As can be seen from the test results of Examples 1, 8, and 9, the process parameters for preparing fatty alcohol modified polyethers provided in this application are all beneficial to improving the defoaming and foam-suppressing abilities of the defoamer, and the changes within the parameter range have little effect on the defoaming time and foam-suppressing time of the defoamer.

[0061] As can be seen from the test results of Examples 1, 10, and 11, the process parameters for preparing organosilane-modified polyethers provided in this application are all beneficial to improving the defoaming and foam-suppressing abilities of the defoamer, and the variation within the parameter range has little effect on the defoaming time and foam-suppressing time of the defoamer.

[0062] As can be seen from the test results of Examples 1, 12, 13 and Comparative Example 7, when the nano silica used in this application is hexadecyl alcohol-modified silica, it is more conducive to improving the defoaming and foam-suppressing abilities of the defoamer.

[0063] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A defoamer with excellent defoaming properties, characterized in that: The raw materials, by weight, include: 23-35 parts of composite polyether, 12-20 parts of modified nano silica, 5-15 parts of composite emulsifier, 5-13 parts of hydrophobic particles, and 25-35 parts of solvent; the composite polyether includes fatty alcohol modified polyether and organosilane modified polyether, with a weight ratio of 1:(1.3-2.5). The fatty alcohol modified polyether mainly comprises the following components: 30-40 parts ethylene oxide, 60-70 parts propylene oxide, 15-25 parts cetyl alcohol, and 3-5 parts catalyst. The organosilane-modified polyether mainly comprises the following components: 10-20 parts polydimethylsiloxane, 35-47 parts ethylene oxide, 53-65 parts propylene oxide, and 5-7 parts catalyst. The modified nano-silica mainly comprises the following components: 25-37 parts nano-silica, 3-5 parts cetyl alcohol; The composite emulsifier comprises fatty acid sucrose ester, polyethylene glycol dilaurate, and Tween 80 in a weight ratio of 1:(1.3-1.5):(1.5-1.9). All ingredients are listed in parts by weight.

2. The method for synthesizing an antifoaming agent with excellent defoaming properties according to claim 1, characterized in that: Includes the following steps: S1. Weigh the fatty alcohol modified polyether and organosilane modified polyether at a weight ratio of 1:(1.3-2.5), add 25-35 parts of solvent and mix evenly to obtain solution A; S2. Mix 12-20 parts of modified nano silica, 5-15 parts of composite emulsifier, and 5-13 parts of hydrophobic particles evenly, add solution A and continue stirring evenly to obtain the defoamer; All ingredients are listed in parts by weight.

3. The method for synthesizing an antifoaming agent with excellent defoaming properties according to claim 2, characterized in that: The preparation method of the organosilane-modified polyether includes the following steps: Mix 10-20 parts of polydimethylsiloxane and 5-7 parts of catalyst evenly, purge with nitrogen, heat to remove moisture, add 35-47 parts of ethylene oxide and 53-65 parts of propylene oxide, react at 100-120℃ for 2-3 hours, stop heating, cool to room temperature, and obtain organosilane modified polyether. All ingredients are listed in parts by weight.

4. The method for synthesizing an antifoaming agent with excellent defoaming properties according to claim 2, characterized in that: The preparation method of the fatty alcohol modified polyether includes the following steps: Mix 15-25 parts of cetyl alcohol and 3-5 parts of catalyst evenly, purge with nitrogen, evacuate, remove moisture, and react at a reaction pressure of 0.01-0.1 MPa and a reaction temperature of 110-130℃ for 3-6 hours. Then continue to raise the temperature to 140-170℃, add 30-40 parts of ethylene oxide and 60-70 parts of propylene oxide, and continue to react for 1-2 hours. After cooling to room temperature, fatty alcohol modified polyether is obtained. All ingredients are listed in parts by weight.

5. The method for synthesizing an antifoaming agent with excellent defoaming properties according to claim 2, characterized in that: The method for preparing the modified nano-silica includes the following steps: 25-37 parts of nano-silica were mixed with 3-5 parts of cetyl alcohol and reacted at a reaction pressure of 0.1-0.5 MPa and a reaction temperature of 180-260℃ for 3-5 hours. After the reaction was completed, the mixture was dried to obtain modified nano-silica. All ingredients are listed in parts by weight.

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