High-solid-content self-emulsifying organic silicon defoaming agent based on ferrocenyl modification and preparation method of high-solid-content self-emulsifying organic silicon defoaming agent

Abstract

The invention relates to the technical field of chemical defoaming agent materials, in particular to a high-solid-content self-emulsifying organic silicon defoaming agent based on ferrocenyl modification and a preparation method thereof.The preparation method comprises the following steps that (S1) under the condition of high-speed stirring, ferrocenyl modified silicon dioxide is added into an oxidizing agent water solution to be stirred, and a mixed solution is obtained; cooling to a low speed, stirring, adding redox response type modified polysiloxane and a polymer steric hindrance stabilizer, continuously stirring, adding dimethyl silicone oil, and stirring to obtain a dispersion liquid; and (S2) adding a nonionic thickener aqueous solution and a reducing agent into the dispersion liquid, and stirring at a high speed to obtain the high-solid-content self-emulsifying organic silicon defoaming agent based on ferrocenyl modification. According to the preparation method, key components of the organic silicon defoaming agent are subjected to ferrocenyl modification, so that the organic silicon defoaming agent is subjected to hydrophilic and hydrophobic intelligent conversion in the preparation process, a self-emulsifying process without additional high energy is realized, and the solid content of the final organic silicon defoaming agent is high.

Description

Technical Field

[0001] This invention relates to the field of chemical defoamer materials technology, specifically to a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified materials and its preparation method. Background Technology

[0002] Organosilicon defoamers are indispensable core additives in many industrial fields, used to eliminate harmful foam generated during the production process. [1, 2] Its core active ingredients (such as polysiloxanes and hydrophobic silica) are inherently strongly hydrophobic and must be processed into an oil-in-water (O / W) emulsion through an emulsification process before they can be used in aqueous systems. [3] .

[0003] However, existing technologies generally face the following technical bottlenecks in the preparation and application of silicone defoamers: Complex process and high energy consumption: Traditional emulsification process relies heavily on high-energy-consuming physical equipment such as high-shear emulsifiers and high-pressure homogenizers to disperse hydrophobic organosilicon into tiny droplets, resulting in large equipment investment and high production costs.

[0004] Poor emulsion stability: As a thermodynamically unstable system, silicone emulsions are prone to problems such as stratification, demulsification, and oil separation when stored or used in harsh industrial environments such as high temperature, high salt, and strong acids and alkalis, leading to a decrease in defoaming performance or even complete failure. [4-6] .

[0005] Negative impacts of emulsifiers: To obtain stable emulsions, large amounts of traditional emulsifiers are required. These non-functional components not only increase costs but may also adversely affect downstream products, such as reducing coating film performance and increasing the chemical oxygen demand (COD) of water treatment systems. [7, 8] .

[0006] The inherent contradiction between high solids content and stability: Increasing the solids content (active ingredient content) of defoamers is an effective way to reduce transportation and storage costs. However, under the current technological framework, high solids content will exacerbate the instability of emulsions, making it difficult to achieve both goals simultaneously.

[0007] In summary, developing a self-emulsifying silicone defoamer that requires no high-energy-consuming equipment, achieves high solids content, and maintains high stability under harsh conditions, as well as its preparation method, is a technical challenge that urgently needs to be solved in this field.

[0008] References: [1] Li Qitao. Research progress and application of organosilicon defoamers [J]. Modern Salt Chemical Industry, 2024, 51(04): 5-6+74. [2] Xu Xuan, Xu Wenyuan, Hu Yafei. Synthesis and performance study of novel modified polyether defoamer [J]. Guangzhou Chemical Industry, 2023, 51(14): 73-76. [3]Chen C., Ren ZR, He YJ Influence of SiO2 Particles on theDefoaming Performance of Silicone Oil Emulsion; proceedings of the 3rdInternational Conference on Mechanical Materials and ManufacturingEngineering (ICMMME 2013), Shanghai, PEOPLES R CHINA, F Oct 01-02, 2013 [C]. [4] Li Xiang. Defoaming mechanism and application of organosilicon defoamers [J]. Chemical Engineer, 2009, 23(01): 47-48. [5] Xu Feng, Dong Dandan, Deng Lei, et al. Compounding and performance study of polyether modified organosilicon defoamer [J]. Organosilicon Materials, 2024, 38(06): 14-24. [6]Langevin D. Influence of interfacial rheology on foam and emulsionproperties [J]. Advances in Colloid and Interface Science, 2000, 88(1): 209-222. [7] Hu Nan, Hu Mingming, Li Zhixin, et al. Research progress and prospects of defoamers[J]. Salt Science and Chemical Engineering, 2021, 50(03): 10-16. [8]Joshi KS, Baumann A., Jeelani SAK, et al. Mechanism of bubblecoalescence induced by surfactant covered antifoam particles [J]. J ColloidInterface Sci, 2009, 339(2): 446-453. Summary of the Invention

[0009] To overcome the shortcomings and deficiencies of existing technologies and address the technical pain points of complex preparation processes, high costs, poor emulsion stability, and difficulty in balancing high solid content and stability in current silicone defoamers, this invention aims to provide a method for preparing a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified materials. This method is green, efficient, and energy-saving. By modifying the key components of the silicone defoamer with ferrocene, it enables a smart transformation during the preparation process, exhibiting a "first hydrophilic, then hydrophobic" transition. This achieves a self-emulsification process without the need for external high-energy additives, and the final silicone defoamer has a solid content as high as 40%-60%. This preparation method is simple to operate, easy to control, has high production efficiency, low production cost, and can be used for large-scale production.

[0010] Another objective of this invention is to provide a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified materials, with a solids content as high as 40%-60%, exhibiting faster defoaming performance and maintaining excellent stability under harsh conditions such as high temperature, high salt, and wide pH range, significantly extending shelf life and effective service life.

[0011] The objective of this invention is achieved through the following technical solution: a method for preparing a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified silicone, comprising the following steps: (S1) Under high-speed stirring conditions, add component A to the aqueous solution of oxidant and stir for 0.5-1.5 h. Then reduce the stirring speed to low speed and add components B and C. Continue stirring for 0.5-1.5 h. Then add dimethyl silicone oil and stir for 0.5-1.5 h to obtain a dispersion. (S2) Add nonionic thickener aqueous solution and reducing agent to dispersion, and then stir at high speed for 1-2 hours to obtain high solid content self-emulsifying organosilicon defoamer based on ferrocene-modified solution; Component A is ferrocene-modified silica, component B is redox-responsive modified polysiloxane, and component C is a polymer steric hindrance stabilizer.

[0012] A high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified silicone was prepared using the above method, forming a self-emulsifier under redox induction. Specifically, step (S1) involves hydrophilic dispersion in an oxidizing state. Components A, B, and C are mixed by conventional stirring in an oxidizing environment composed of water and an oxidant. At this point, the ferrocene groups in components A and B are in a hydrophilic oxidizing state. The added dimethyl silicone oil is encapsulated by components B and C in the oxidant aqueous solution. Here, components B and C act as emulsifiers in the oxidizing environment, allowing for easy and uniform emulsification. The mixture is evenly dispersed to form a uniform dispersion with high solids content. Step (S2) is reduction-induced self-emulsification. Under continuous stirring, a reducing agent is added to the dispersion. The reducing agent causes the ferrocene cations in components A and B to be rapidly reduced to hydrophobic groups. This in-situ, rapid hydrophilic-hydrophobic transition leads to an instantaneous change in interfacial tension. Under the synergistic effect of component C, the hydrophobic components A and B spontaneously aggregate into tiny droplets. Without high shear or high pressure homogenization, a high solids content oil-in-water (O / W) type defoamer emulsion with uniform particle size and stable structure can be formed.

[0013] Furthermore, in step (S1), the high-speed stirring speed is 900-1500 rpm, and the low-speed stirring speed is 200-400 rpm; the viscosity range of the dimethyl silicone oil is 100-10000 cSt. As one of the core components of the defoamer, the dimethyl silicone oil spreads to the surface of the liquid film during defoaming, working synergistically with other components to pierce the liquid film and ensure defoaming performance. In step (S2), the high-speed stirring speed is 900-1500 rpm.

[0014] Preferably, the concentration of the oxidant aqueous solution is 0.1-0.5 mol / L, and the concentration of the nonionic thickener aqueous solution is 0.1-0.3 wt%; the oxidant in the oxidant aqueous solution is at least one selected from ammonium persulfate, ferric sulfate, ferric chloride, hydrogen peroxide, and cerium ammonium nitrate; the nonionic thickener in the nonionic thickener aqueous solution is a polyurethane thickener; and the reducing agent is at least one selected from L-ascorbic acid, sodium borohydride, sodium sulfite, and sodium bisulfite. More preferably, the oxidant is ferric sulfate, and the reducing agent is L-ascorbic acid. Studies have shown that ferric sulfate and L-ascorbic acid have relatively high oxidation and reduction efficiencies for ferrocene groups, and the reaction is more environmentally friendly.

[0015] Preferably, the weight ratio of the oxidant aqueous solution, component A, component B, component C, dimethyl silicone oil, and nonionic thickener aqueous solution is 90-110:5-10:10-20:5-10:90-110:10-50, and the molar number of the reducing agent is 1-1.05 times the molar number of the oxidant.

[0016] More preferably, the nonionic thickener in the aqueous solution is selected from models RM-8W, FX1010, and FX 1070. This system has good compatibility and utilizes a nonionic thickener to stabilize the emulsion.

[0017] Preferably, the preparation method of the ferrocene-based modified silica includes the following steps: (A1) Take 0.14-0.42 parts by weight of ferrocene carboxylic acid and 60-68 parts by weight of dichloromethane, and stir and dissolve them at room temperature under argon protection for 25-40 minutes. (A2) Add 0.6-2.3 parts of oxalyl chloride, heat under reflux for 2-8 hours, remove dichloromethane and the remaining oxalyl chloride using a diaphragm pump, add 75-83 parts of dichloromethane to redissolve, transfer to a reaction flask containing 0.8-1.2 parts of silica and 60-68 parts of dichloromethane, and continue to stir the reaction at room temperature for 5-24 hours under argon protection. (A3) After filtration with a microporous membrane, the silica was washed 1-3 times with deionized water and anhydrous ethanol, and then dried under vacuum to obtain ferrocene-based modified silica, abbreviated as SiO2-Fc.

[0018] Ferrocene-based modified silica was prepared using the above method with a yield of approximately 85-92%. Nano-silica was used as a carrier, and ferrocene groups were bonded to the surface. These groups served as the core solid defoaming active sites and response units. In the oxidized state, the ferrocene groups were hydrophilic cations, making the particles easy to disperse in water. In the reduced state, they reverted to hydrophobic ferrocene, thus exerting the defoaming effect.

[0019] Preferably, the silica is hydrophilic fumed silica that has been vacuum dried at 80°C for 12 hours; the vacuum drying process is performed at 60°C for 3-12 hours; and the pore size of the microporous filter membrane is 0.22 micrometers.

[0020] Preferably, the preparation method of the redox-responsive modified polysiloxane includes the following steps: (B1) By weight, under argon protection, 10.0 parts of hydrogen-containing silicone oil, 0.220-0.353 parts of allyl ferrocene carboxylate (ACOFc), 0.360-0.720 parts of allyl polyoxyethylene methyl-terminated polyether (APEG) and 0.020 parts of platinum catalyst are mixed and stirred at room temperature for 20-30 minutes to obtain a mixture. (B2) Heat the mixture to 75-85°C and react for 2-6 hours, then raise the temperature to 135-145°C and continue the reaction for 1-2 hours to obtain a reddish-brown viscous liquid with an HLB value of 4-7, which is a redox-responsive modified polysiloxane, abbreviated as SO-ACOFc-APEG.

[0021] The above method was used to prepare redox-responsive modified polysiloxanes with a yield of approximately 98%. The polysiloxane backbone was simultaneously grafted with hydrophilic segments and hydrophobic regulating segments containing ferrocene groups. As a responsive oil phase host and HLB (hydrophilic-lipophilic balance) value regulating unit, it plays a dual role in emulsification and defoaming. Its overall HLB value can be controlled by the redox state: in the oxidized state, the hydrophilicity is enhanced and it is easy to disperse; in the reduced state, the hydrophobicity is restored, becoming a typical oil phase.

[0022] Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.15-0.25 wt%; and the Pt concentration of the platinum catalyst is 1000 ppm.

[0023] Preferably, the preparation method of the polymer steric hindrance stabilizer includes the following steps: (C1) By weight, 11-13 parts of polyethylene glycol 6000 and 85-100 parts of toluene are mixed, heated under argon protection and refluxed, and the water is separated by a water separator. (C2) Add 0.90-0.98 parts of isophorone diisocyanate and 0.030-0.050 parts of organotin catalyst to the reaction system, raise the temperature to 75-85°C, and keep the temperature constant for 2-4 hours; (C3) Add single-hydroxyl silicone oil to the reaction system and continue to react at 75-85°C for 2-4 hours. Then, raise the temperature to 88-93°C and react for 1-2 hours. Pour it into 220-240 parts of petroleum ether at 60-90°C, stir to precipitate the polymer, let it stand for 5-10 hours, filter, and take the precipitate. (C4) Dissolve the precipitate in 23-30 parts toluene, and repeat the precipitation once in 220-240 parts petroleum ether. Then, dry it under vacuum to obtain a white solid with an HLB value of 11-15, which is the polymer steric hindrance stabilizer, abbreviated as SO-PEG-SO.

[0024] The polymer steric hindrance stabilizer prepared using the above method has a yield of approximately 95%. As a long-lasting stabilizer and primary emulsifier, it utilizes a nonionic block copolymer (polysiloxane-polyether-polysiloxane copolymer) with a fixed high HLB value. After emulsion formation, its long-chain structure provides strong steric hindrance protection, ensuring the long-term storage stability and environmental tolerance of the emulsion. Polyethylene glycol 6000 itself is highly hygroscopic; therefore, water is separated using a water separator before the reaction to prevent water from subsequently disrupting the polyurethane reaction.

[0025] Preferably, the organotin catalyst is a dibutyltin dilaurate catalyst; the molar ratio of the single-hydroxyl-terminated silicone oil to polyethylene glycol 6000 is 4.2-4.8:2; and the vacuum drying treatment is performed at 40°C for 48 hours.

[0026] Another objective of the present invention is achieved by the following technical solution: the above-mentioned high solids content self-emulsifying silicone defoamer based on ferrocene-modified material is prepared by the preparation method of the high solids content self-emulsifying silicone defoamer based on ferrocene-modified material described above.

[0027] The beneficial effects of this invention are as follows: Compared with the prior art, this invention has the following significant technical advantages and highlights: 1. The preparation method of the high solid content self-emulsifying organosilicon defoamer based on ferrocene-modified according to the present invention achieves self-emulsification, greatly simplifies the process and reduces costs: by utilizing the chemically induced "self-emulsification" effect, it completely gets rid of the dependence on expensive and energy-intensive equipment such as high-pressure homogenizers, making the production process simpler, the cost lower and easier to scale up production.

[0028] 2. The preparation method of this organosilicon defoamer breaks through the bottleneck of "high solid content-stability": through a two-step strategy of "first hydrophilic dispersion, then in-situ hydrophobicization", a stable emulsion with a solid content of up to 40%-60% (or even higher) can be easily prepared at low viscosity, which significantly improves the active ingredient content per unit product and reduces transportation and storage costs.

[0029] 3. The high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified material of the present invention has excellent stability and environmental tolerance: the reversible redox properties of ferrocene-based material endow the emulsion with a unique "intelligent" stabilization mechanism, combined with the steric hindrance protection of the highly efficient polymer stabilizer C, so that the product can still maintain excellent stability under harsh conditions such as high temperature, high salt, and wide pH range, significantly extending the shelf life and effective service life.

[0030] 4. The high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified material of the present invention has high product purity and good compatibility with downstream applications: the self-emulsifying system greatly reduces the dependence on traditional small molecule emulsifiers, avoids the potential negative impact of non-functional additives on downstream applications such as coating adhesion, skin feel of daily chemical products, and COD index of water treatment, and improves the application quality and universality of the product. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the molecular structure and redox reversible regulation process of components A, B and C as described in Example 1 of the present invention; Figure 2 This is a schematic diagram of the synthetic route of component A described in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the synthetic route of component B described in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the synthetic route of component C described in Embodiment 1 of the present invention; Figure 5 This is a comparison of the infrared spectra of component A and its raw materials as described in Example 1 of the present invention; Figure 6 This is a comparison of the infrared spectra of component B and its raw materials as described in Example 1 of the present invention; Figure 7 This is a comparison of the infrared spectra of component C and its raw materials as described in Example 1 of the present invention; Figure 8 This is a TG curve of component A and hydrophilic fumed silica as described in Example 1 of the present invention; Figure 9 This is the TG curve of component B and component C as described in Example 1 of the present invention. Detailed Implementation

[0032] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0033] Example 1 like Figure 1 As shown, a method for preparing a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified silicone includes the following steps: (S1) Under high-speed stirring at 1000 rpm, 8 g of component A was slowly added to 90-110 g of oxidant aqueous solution and stirred for 1 h. Then the stirring speed was reduced to 300 rpm and 15 g of component B and 8 g of component C were added. Stirring was continued for 1 h. Then 100 g of dimethyl silicone oil was added and stirred for 1 h to obtain a dispersion. (S2) Slowly add 30 g of nonionic thickener aqueous solution and reducing agent (the molar number of which is 1.02 times the molar number of oxidant) to the dispersion, and then stir at high speed of 1000 rpm for 1 h to obtain a high solid content self-emulsifying organosilicon defoamer based on ferrocene-modified solution. Component A is ferrocene-modified silica, component B is redox-responsive modified polysiloxane, component C is a polymer steric hindrance stabilizer, and dimethyl silicone oil is selected from Dow Corning PMX200.

[0034] The concentration of the oxidant aqueous solution is 0.3 mol / L, and the concentration of the nonionic thickener aqueous solution is 0.2 wt%; the oxidant in the oxidant aqueous solution is ferric sulfate; the nonionic thickener in the nonionic thickener aqueous solution is selected from model RM-8W; the reducing agent is L-ascorbic acid.

[0035] like Figure 2 As shown, the preparation method of the ferrocene-based modified silica includes the following steps: (A1) Take 0.26 g of ferrocene carboxylic acid and 50 ml of dichloromethane, and stir and dissolve them at room temperature for 30 min under argon protection; (A2) Add 1 ml of oxalyl chloride, heat under reflux for 6 h, remove dichloromethane and the remaining oxalyl chloride using a diaphragm pump, add 60 ml of dichloromethane to redissolve, transfer to a reaction flask containing 1 g of silica and 50 ml of dichloromethane, and continue to stir the reaction at room temperature for 12 h under argon protection. (A3) Filter with a microporous membrane with a pore size of 0.22 micrometers, wash twice with deionized water and twice with anhydrous ethanol, and then vacuum dry to obtain ferrocene-based modified silicon dioxide, abbreviated as SiO2-Fc.

[0036] The silica is hydrophilic fumed silica (Degussa A200) that has been vacuum dried at 80°C for 12 hours; the vacuum drying process is performed at 60°C for 6 hours.

[0037] like Figure 3 As shown, the preparation method of the redox-responsive modified polysiloxane includes the following steps: (B1) Under argon protection, 10.0 g of hydrogen-containing silicone oil, 0.28 g of allyl ferrocene carboxylate (ACOFc), 0.540 g of allyl polyoxyethylene methyl-terminated polyether (APEG) and 0.020 g of PT-1000 platinum catalyst were mixed and stirred at room temperature for 30 min to obtain a mixture. (B2) Heat the mixture to 80°C and react for 4 hours, then raise the temperature to 140°C and continue the reaction for 1.5 hours to obtain a reddish-brown viscous liquid with an HLB value of 4-7, which is a redox-responsive modified polysiloxane, abbreviated as SO-ACOFc-APEG.

[0038] The hydrogen content of the hydrogen-containing silicone oil is 0.18 wt%; the Pt concentration of the platinum catalyst is 1000 ppm.

[0039] like Figure 4 As shown, the preparation method of the polymer steric hindrance stabilizer includes the following steps: (C1) Mix 12g of polyethylene glycol 6000 and 100ml of toluene, heat under argon protection and reflux, and separate the water using a water separator; (C2) Add 0.93 g of isophorone diisocyanate and 0.039 g of organotin catalyst to the reaction system, raise the temperature to 80°C, and keep the reaction at a constant temperature for 3 h; (C3) Add single-hydroxyl silicone oil to the reaction system and continue to react at 80°C for 3 hours. Then, raise the temperature to 90°C and react for 1.5 hours. Pour it into 300 ml of petroleum ether at 80°C, stir to precipitate the polymer, let it stand for 8 hours, filter and take the precipitate. (C4) Dissolve the precipitate in 30 ml of toluene and repeat the precipitation once in 300 ml of petroleum ether. Then, dry it under vacuum to obtain a white solid with an HLB value of 11-15, which is the polymer steric hindrance stabilizer, abbreviated as SO-PEG-SO.

[0040] The organotin catalyst is dibutyltin dilaurate catalyst; the molar ratio of the single-hydroxyl-terminated silicone oil to polyethylene glycol 6000 is 4.62:2; the vacuum drying treatment is performed at 40°C for 48 hours.

[0041] Example 2 A method for preparing a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified silicone includes the following steps: (S1) Under high-speed stirring at 1000 rpm, 5 g of component A was slowly added to 90 g of oxidant aqueous solution and stirred for 1 h. Then the stirring speed was reduced to 300 rpm and 10 g of component B and 5 g of component C were added. Stirring was continued for 1 h. Then 100 g of dimethyl silicone oil was added and stirred for 1 h to obtain a dispersion. (S2) Slowly add 15 g of nonionic thickener aqueous solution and reducing agent (the molar number of which is 1.01 times the molar number of oxidant) to the dispersion, and then stir at high speed of 1000 rpm for 1 h to obtain a high solid content self-emulsifying organosilicon defoamer based on ferrocene-modified solution. Component A is ferrocene-modified silica, component B is redox-responsive modified polysiloxane, component C is a polymer steric hindrance stabilizer, and dimethyl silicone oil is selected from Dow Corning PMX200.

[0042] The concentration of the oxidant aqueous solution is 0.2 mol / L, and the concentration of the nonionic thickener aqueous solution is 0.1 wt%; the oxidant in the oxidant aqueous solution is ammonium persulfate; the nonionic thickener in the nonionic thickener aqueous solution is selected from model FX 1010; the reducing agent is L-ascorbic acid.

[0043] The preparation method of the ferrocene-based modified silica includes the following steps: (A1) Take 0.15 g of ferrocene carboxylic acid and 50 ml of dichloromethane, and stir and dissolve them at room temperature for 30 min under argon protection; (A2) Add 0.5 ml of oxalyl chloride, heat under reflux for 3 h, remove dichloromethane and the remaining oxalyl chloride using a diaphragm pump, add 60 ml of dichloromethane to redissolve, transfer to a reaction flask containing 0.9 g of silica and 50 ml of dichloromethane, and continue to stir the reaction at room temperature for 6 h under argon protection. (A3) Filter with a microporous membrane with a pore size of 0.22 micrometers, wash twice with deionized water and twice with anhydrous ethanol, and then vacuum dry to obtain ferrocene-based modified silicon dioxide, abbreviated as SiO2-Fc.

[0044] The silica is hydrophilic fumed silica (Degussa A200) that has been vacuum dried at 80°C for 12 hours; the vacuum drying process is performed at 60°C for 6 hours.

[0045] The preparation method of the redox-responsive modified polysiloxane includes the following steps: (B1) Under argon protection, 10.0 g of hydrogen-containing silicone oil, 0.222 g of allyl ferrocene formaldehyde (ACOFc), 0.365 g of allyl polyoxyethylene methyl-terminated polyether (APEG) and 0.020 g of PT-1000 platinum catalyst were mixed and stirred at room temperature for 30 min to obtain a mixture. (B2) Heat the mixture to 80°C and react for 3 hours, then raise the temperature to 140°C and continue the reaction for 1 hour to obtain a reddish-brown viscous liquid with an HLB value of 4-7, which is a redox-responsive modified polysiloxane, abbreviated as SO-ACOFc-APEG.

[0046] The hydrogen content of the hydrogen-containing silicone oil is 0.18 wt%; the Pt concentration of the platinum catalyst is 1000 ppm.

[0047] The preparation method of the polymer steric hindrance stabilizer includes the following steps: (C1) Mix 12g of polyethylene glycol 6000 and 100ml of toluene, heat under argon protection and reflux, and separate the water using a water separator; (C2) Add 0.91 g of isophorone diisocyanate and 0.031 g of organotin catalyst to the reaction system, raise the temperature to 80°C, and keep the reaction at a constant temperature for 2 h; (C3) Add single-hydroxyl silicone oil to the reaction system and continue to react at 80°C for 2 hours. Then, raise the temperature to 90°C and react for 1 hour. Pour it into 300 ml of petroleum ether at 80°C, stir to precipitate the polymer, let it stand for 8 hours, filter and take the precipitate. (C4) Dissolve the precipitate in 30 ml of toluene and repeat the precipitation once in 300 ml of petroleum ether. Then, dry it under vacuum to obtain a white solid with an HLB value of 11-15, which is the polymer steric hindrance stabilizer, abbreviated as SO-PEG-SO.

[0048] The organotin catalyst is dibutyltin dilaurate catalyst; the molar ratio of the single-hydroxyl-terminated silicone oil to polyethylene glycol 6000 is 4.3:2; the vacuum drying treatment is performed at 40°C for 48 hours.

[0049] Example 3 A method for preparing a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified silicone includes the following steps: (S1) Under high-speed stirring at 1000 rpm, 10 g of component A was slowly added to 110 g of oxidant aqueous solution and stirred for 1 h. Then the stirring speed was reduced to 300 rpm and 20 g of component B and 10 g of component C were added. Stirring was continued for 1 h. Then 110 g of dimethyl silicone oil was added and stirred for 1 h to obtain a dispersion. (S2) Slowly add 50 g of nonionic thickener aqueous solution and reducing agent (the molar number of which is 1.05 times the molar number of oxidant) to the dispersion, and then stir at high speed of 1000 rpm for 2 h to obtain a high solid content self-emulsifying organosilicon defoamer based on ferrocene-modified solution. Component A is ferrocene-modified silica, component B is redox-responsive modified polysiloxane, component C is a polymer steric hindrance stabilizer, and dimethyl silicone oil is selected from Dow Corning PMX200.

[0050] The concentration of the oxidant aqueous solution is 0.5 mol / L, and the concentration of the nonionic thickener aqueous solution is 0.3 wt%; the oxidant in the oxidant aqueous solution is ferric sulfate; the nonionic thickener in the nonionic thickener aqueous solution is selected from model RM-8W; the reducing agent is L-ascorbic acid.

[0051] The preparation method of the ferrocene-based modified silica includes the following steps: (A1) Take 0.42 g of ferrocene carboxylic acid and 50 ml of dichloromethane, and stir and dissolve them at room temperature for 30 min under argon protection; (A2) Add 1.5 ml of oxaloyl chloride, heat under reflux for 8 h, remove dichloromethane and the remaining oxaloyl chloride using a diaphragm pump, add 60 ml of dichloromethane to redissolve, transfer to a reaction flask containing 1.2 g of silica and 50 ml of dichloromethane, and continue to stir the reaction at room temperature for 24 h under argon protection. (A3) Filter with a microporous membrane with a pore size of 0.22 micrometers, wash twice with deionized water and twice with anhydrous ethanol, and then vacuum dry to obtain ferrocene-based modified silicon dioxide, abbreviated as SiO2-Fc.

[0052] The silica is hydrophilic fumed silica (Degussa A200) that has been vacuum dried at 80°C for 12 hours; the vacuum drying process is performed at 60°C for 6 hours.

[0053] The preparation method of the redox-responsive modified polysiloxane includes the following steps: (B1) Under argon protection, 10.0 g of hydrogen-containing silicone oil, 0.353 g of allyl ferrocene carboxylate ACOFc, 0.720 g of allyl polyoxyethylene methyl-terminated polyether APEG and 0.020 g of PT-1000 platinum catalyst were mixed and stirred at room temperature for 30 min to obtain a mixture. (B2) Heat the mixture to 80°C and react for 6 hours, then raise the temperature to 140°C and continue the reaction for 2 hours to obtain a reddish-brown viscous liquid with an HLB value of 4-7, which is a redox-responsive modified polysiloxane, abbreviated as SO-ACOFc-APEG.

[0054] The hydrogen content of the hydrogen-containing silicone oil is 0.18 wt%; the Pt concentration of the platinum catalyst is 1000 ppm.

[0055] The preparation method of the polymer steric hindrance stabilizer includes the following steps: (C1) Mix 12g of polyethylene glycol 6000 and 100ml of toluene, heat under argon protection and reflux, and separate the water using a water separator; (C2) Add 0.98 g of isophorone diisocyanate and 0.050 g of organotin catalyst to the reaction system, raise the temperature to 80°C, and keep the reaction at a constant temperature for 4 h; (C3) Add single-hydroxyl silicone oil to the reaction system and continue to react at 80°C for 4 hours. Then, raise the temperature to 90°C and react for 2 hours. Pour it into 300 ml of petroleum ether at 80°C, stir to precipitate the polymer, let it stand for 10 hours, filter and take the precipitate. (C4) Dissolve the precipitate in 30 ml of toluene and repeat the precipitation once in 300 ml of petroleum ether. Then, dry it under vacuum to obtain a white solid with an HLB value of 11-15, which is the polymer steric hindrance stabilizer, abbreviated as SO-PEG-SO.

[0056] The organotin catalyst is dibutyltin dilaurate catalyst; the molar ratio of the single-hydroxyl-terminated silicone oil to polyethylene glycol 6000 is 4.8:2; the vacuum drying treatment is vacuum drying at 40°C for 48 hours.

[0057] Comparative Example 1 An organosilicon defoamer, selected from Dow Chemical's Antifoam 554.

[0058] Comparative Example 2 An organosilicon defoamer, selected from BYK-024.

[0059] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the high-solids-content self-emulsifying silicone defoamer does not contain component B.

[0060] Specifically, a method for preparing an organosilicon defoamer includes the following steps: (S1) Under high-speed stirring at 1000 rpm, 23 g of component A was slowly added to 90-110 g of oxidant aqueous solution and stirred for 1 h. Then the stirring speed was reduced to 300 rpm and 8 g of component C was added. Stirring was continued for 1 h. Then 100 g of dimethyl silicone oil was added and stirred for 1 h to obtain a mixture. (S2) Slowly add 30 g of nonionic thickener aqueous solution and reducing agent (the molar number of which is 1.02 times the molar number of oxidant) to the mixture, and then stir at high speed of 1000 rpm for 1 h to obtain organosilicon defoamer; Component A is ferrocene-modified silica, component C is a polymer steric hindrance stabilizer, and dimethyl silicone oil is selected from Dow Corning PMX200.

[0061] The concentration of the oxidant aqueous solution is 0.3 mol / L, and the concentration of the nonionic thickener aqueous solution is 0.2 wt%; the oxidant in the oxidant aqueous solution is ferric sulfate; the nonionic thickener in the nonionic thickener aqueous solution is selected from model RM-8W; the reducing agent is L-ascorbic acid.

[0062] The preparation method of the ferrocene-based modified silica includes the following steps: (A1) Take 0.26 g of ferrocene carboxylic acid and 50 ml of dichloromethane, and stir and dissolve them at room temperature for 30 min under argon protection; (A2) Add 1 ml of oxalyl chloride, heat under reflux for 6 h, remove dichloromethane and the remaining oxalyl chloride using a diaphragm pump, add 60 ml of dichloromethane to redissolve, transfer to a reaction flask containing 1 g of silica and 50 ml of dichloromethane, and continue to stir the reaction at room temperature for 12 h under argon protection. (A3) Filter with a microporous membrane with a pore size of 0.22 micrometers, wash twice with deionized water and twice with anhydrous ethanol, and then vacuum dry to obtain ferrocene-based modified silicon dioxide, abbreviated as SiO2-Fc.

[0063] The silica is hydrophilic fumed silica (Degussa A200) that has been vacuum dried at 80°C for 12 hours; the vacuum drying process is performed at 60°C for 6 hours.

[0064] The preparation method of the polymer steric hindrance stabilizer includes the following steps: (C1) Mix 12g of polyethylene glycol 6000 and 100ml of toluene, heat under argon protection and reflux, and separate the water using a water separator; (C2) Add 0.93 g of isophorone diisocyanate and 0.039 g of organotin catalyst to the reaction system, raise the temperature to 80°C, and keep the reaction at a constant temperature for 3 h; (C3) Add single-hydroxyl silicone oil to the reaction system and continue to react at 80°C for 3 hours. Then, raise the temperature to 90°C and react for 1.5 hours. Pour it into 300 ml of petroleum ether at 80°C, stir to precipitate the polymer, let it stand for 8 hours, filter and take the precipitate. (C4) Dissolve the precipitate in 30 ml of toluene and repeat the precipitation once in 300 ml of petroleum ether. Then, dry it under vacuum to obtain a white solid with an HLB value of 11-15, which is the polymer steric hindrance stabilizer, abbreviated as SO-PEG-SO.

[0065] The organotin catalyst is dibutyltin dilaurate catalyst; the molar ratio of the single-hydroxyl-terminated silicone oil to polyethylene glycol 6000 is 4.62:2; the vacuum drying treatment is performed at 40°C for 48 hours.

[0066] Testing and Characterization: I. Based on Example 1, test the infrared spectra of component A and its raw materials, test the infrared spectra of component B and its raw materials, and test the infrared spectra of component C and its raw materials. The test conditions are as follows: Fourier transform infrared spectroscopy (FT-IR), instrument: Nicolet 6700 Fourier transform infrared spectrometer (Thermo Scientific, USA). Test method: ATR total reflection mode, germanium crystal, scanning range 600–4000 cm⁻¹. -1 .

[0067] Test results are as follows Figure 5-7 As shown.

[0068] from Figure 5 The infrared spectra of fumed silica (SiO2), ferrocene carboxylic acid (FcCOOH), and ferrocene-modified silica (SO2-Fc) are shown. In these infrared spectra, an antisymmetric stretching vibration peak of Si-O-Si (1092 cm⁻¹) is observed. -1 and 809 cm -1 ) and the characteristic absorption peak of FcCOOH (1655 cm⁻¹) -1 and 1475 cm -1 These absorption peaks indicate that ferrocene groups were successfully grafted onto the surface of fumed silica via esterification, successfully preparing component A (SiO2-Fc).

[0069] from Figure 6The infrared spectra of allyl ferrocene (ACOFc), allyl polyoxyethylene methyl-terminated polyether (APEG), and component B (SO-ACOFc-APEG) are shown. In this infrared spectrum, the -CH2- stretching vibration peak of APEG (2879 cm⁻¹) is observed. -1 ) and COC antisymmetric stretching vibration peak (1106 cm) -1 ), and the characteristic absorption peak of ACOFc (1718 cm⁻¹). -1 and 1458 cm -1 In addition, the characteristic Si-H absorption peak of hydrogen-containing silicone oil (2155 cm⁻¹) is observed. -1 The disappearance of the ) indicates that ACOFc and APEG were successfully grafted onto the side chain of the hydrogen-containing silicone oil via hydrosilylation reaction, thus successfully preparing component B (SO-ACOFc-APEG).

[0070] from Figure 7 The infrared spectra of polyethylene glycol 6000 (PEG6000), single-hydroxyl-terminated silicone oil (SHSO), and component C (SO-PEG-SO) are shown. In this infrared spectrum, the characteristic absorption peak of PEG6000 (2884 cm⁻¹) is observed. -1 and 1467 cm -1 ) and the characteristic absorption peak of SHSO (2962 cm⁻¹) -1 and 1259 cm -1 Meanwhile, the characteristic absorption peak of isocyanate group -NCO (2200–2300 cm⁻¹) is observed. -1 The disappearance of SHSO indicates that SHSO was successfully grafted to both ends of PEG6000 via a polyurethane reaction, and component C (SO-PEG-SO) was successfully prepared.

[0071] II. Thermal stability analysis (TG) of the material Based on Example 1, the TG curves of component A and hydrophilic fumed silica were tested, and the TG curves of component B and component C were tested. The testing method is as follows: According to the group standard TFSI 131-2023 "Determination of Hydroxyl Content in Fumed Silica - TGA Method", the sample was tested by thermogravimetric analysis (TG). The thermogravimetric analysis (TGA) was performed using a TGA 8000 thermogravimetric analyzer (PerkinElmer Instruments Co., Ltd.). Test conditions: Under a nitrogen atmosphere (gas flow rate 20 ml / min), approximately 8 mg of sample was placed in an alumina crucible, and the temperature was increased to 600℃ at a rate of 10℃ / min. The sample mass loss curve was recorded.

[0072] Test results are as follows Figure 8-9 As shown.

[0073] from Figure 8 The TG curves of hydrophilic fumed silica and component A (SiO2-Fc) are shown below: The hydrophilic fumed silica (Evonik Degussa A200) has a mass fraction of 97.80% after removing physically adsorbed water at 105℃ and 96.16% at 800℃, resulting in a calculated silanol content of 3.10%. Component A (SiO2-Fc) begins to decompose at approximately 140℃, with the weight loss ending at 352℃, at which point the mass fraction is 76.17%, and the residual mass at 800℃ is 74.28%. This suggests that approximately 22.3% of ferrocene acid was successfully grafted onto the fumed silica surface via esterification, with a slight decrease in thermal stability after grafting.

[0074] from Figure 9 The TG curves for components B and C are shown below: Component B (SO-ACOFc-APEG) begins to decompose at approximately 254℃, exhibiting better thermal stability. In contrast, component C (SO-PEG-SO) shows superior thermal stability, decomposing only at approximately 323℃. These results indicate that different molecular structures significantly affect the thermal decomposition properties of the material.

[0075] III. Defoaming performance test: The silicone defoamers of Example 1 and Comparative Examples 1-3 were subjected to appearance observation and defoaming performance testing. Method for visual observation: Take 10 ml of the silicone defoamer from Example 1 and Comparative Examples 1-3 respectively, and observe the phenomenon of the liquid.

[0076] Defoaming performance test was conducted according to the national standard GB / T 26527-2024 "Determination of Defoaming Performance of Organosilicon Defoamers" (hand-shaking method). Test method: Prepare the foaming solution by dissolving 5.0 g of fatty alcohol polyoxyethylene ether (AEO-9) and 5.0 g of sodium dodecylbenzenesulfonate in 990 mL of deionized water and stirring until homogeneous and transparent. Take 50 mL of the foaming solution into a custom-made square plastic bottle, add 0.05 g of each test defoamer to a solid content of 10 wt%, and after capping the bottle, shake it up and down 10, 100, and 1000 times at a frequency of 2 times / second and an amplitude of 30-35 cm. Record the time required for the foam to subside to the liquid surface (unit: seconds).

[0077] The test results are shown in Table 1 below:

[0078] As shown in Table 1, compared with Comparative Examples 1-3, the silicone defoamer based on ferrocene-modified silicone material in Example 1 exhibits faster defoaming performance and better stability. Comparative Example 3, lacking component B, cannot synergize with component C. The hydrophobic substance (dimethyl silicone oil) is not easily emulsified, the system is too hydrophilic, making it difficult to obtain a stable emulsion. The hydrophobic substance gradually aggregates to form an oil layer or precipitate, causing the system to separate into layers. Unemulsified hydrophobic substances are suspended in the liquid, making the originally uniform emulsion turbid. Furthermore, they cannot quickly migrate to the bubble surface, resulting in a slower defoaming speed. Their effect of reducing surface tension is weakened, the bubbles are more stable, and they cannot achieve excellent defoaming effects. Even in the defoaming performance test, a long wait is required after more than 100 hand-shaking cycles before gradual defoaming.

[0079] The reversible redox properties of the ferrocene-based emulsion in this invention endow the emulsion with a unique "intelligent" stabilization mechanism. Combined with the steric hindrance protection of the polymer steric hindrance stabilizer, the product can maintain excellent stability under harsh conditions such as high temperature, high salt, and wide pH range.

[0080] This invention successfully developed a high-solids-content self-emulsifying silicone defoamer based on ferrocene-modified materials and its preparation method, effectively solving the core technical problems of traditional silicone defoamers in terms of production process, product stability and application compatibility.

[0081] This invention achieves a revolutionary self-emulsifying production process: by introducing ferrocene-based components as a redox-responsive switch, it utilizes a chemically induced phase transition of "first hydrophilic, then hydrophobic" to achieve spontaneous emulsification of the defoamer's active components in water. This innovation completely eliminates the reliance on energy-intensive physical equipment such as high-shear and high-homogeneity equipment, significantly simplifying the production process and reducing equipment investment and production costs.

[0082] This invention overcomes the inherent contradiction between high solids content and stability: its two-step method (oxidative dispersion-reduced emulsification) allows for the formation of stable and homogeneous emulsions even at high solids content (40wt%-60wt% or even higher). This fundamentally solves the bottleneck of emulsion instability caused by high solids content in traditional technologies, significantly increasing the concentration of effective active ingredients in the product and reducing transportation and storage costs.

[0083] This product exhibits exceptional stability and environmental tolerance: Combining the reversible redox properties of ferrocene-based compounds with the dual protection mechanism of polymer steric hindrance stabilizers, this defoamer emulsion demonstrates excellent stability under harsh industrial conditions such as high temperature, high salt, and wide pH range, effectively extending the product's shelf life and service life, and avoiding production problems caused by demulsification failure.

[0084] Improved product purity and compatibility with downstream applications: Because the self-emulsifying system significantly reduces reliance on traditional small-molecule emulsifiers, the product has higher purity and avoids the negative impact of these non-functional additives on downstream applications (such as coating film performance, water treatment COD index, etc.), making the product more widely applicable and of higher application quality.

[0085] In summary, this invention, through an innovative chemical self-emulsification strategy, provides the market with a new generation of high-solids-content silicone defoamers that are highly efficient, stable in performance, cost-effective, and environmentally friendly, possessing significant economic value and broad application prospects.

[0086] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A process for the preparation of high solids self-emulsifying organosilicon defoamer based on ferrocene-based modification, characterized by, Comprising the following steps: (S1), under high-speed stirring conditions, adding component A to the aqueous oxidizing agent solution, stirring for 0.5-1.5h, then reducing to low-speed stirring and adding component B and component C, continuing to stir for 0.5-1.5h, then adding dimethyl silicone oil, stirring for 0.5-1.5h, to obtain a dispersion liquid; (S2), adding an aqueous non-ionic thickening agent solution and a reducing agent to the dispersion liquid, then high-speed stirring for 1-2h, to obtain a ferrocene-based modified high-solid-content self-emulsifying silicone defoamer; Among them, component A is ferrocene-based modified silica, component B is redox-responsive modified polysiloxane, and component C is a polymer steric stabilizer.

2. The preparation method of high solid content self-emulsifying organosilicon defoamer based on ferrocene group modification according to claim 1, characterized in that: The concentration of the aqueous oxidizing agent solution is 0.1-0.5mol / L, and the concentration of the aqueous non-ionic thickening agent solution is 0.1-0.3wt%; the oxidizing agent of the aqueous oxidizing agent solution is at least one of ammonium persulfate, ferric sulfate, ferric chloride, hydrogen peroxide and cerium ammonium nitrate; the non-ionic thickening agent of the aqueous non-ionic thickening agent solution is a polyurethane thickening agent; the reducing agent is at least one of L-ascorbic acid, sodium borohydride, sodium sulfite and sodium bisulfite.

3. The preparation method of high solid content self-emulsifying organosilicon defoamer based on ferrocene group modification according to claim 1, characterized in that: The weight ratio of the aqueous oxidizing agent solution, component A, component B, component C, dimethyl silicone oil and aqueous non-ionic thickening agent solution is 90-110:5-10:10-20:5-10:90-110:10-50, and the number of moles of the reducing agent is 1-1.05 times the number of moles of the oxidizing agent.

4. The preparation method of high solid content self-emulsifying organosilicon defoamer based on ferrocene group modification according to claim 1, characterized in that, The preparation method of the ferrocene-based modified silica comprises the following steps: (A1), taking 0.14-0.42 parts of ferrocene formic acid and 60-68 parts of dichloromethane by weight, stirring and dissolving at room temperature under argon protection for 25-40min; (A2), adding 0.6-2.3 parts of oxalyl chloride, heating and refluxing for 2-8h, then removing the dichloromethane and residual oxalyl chloride using a diaphragm pump, then adding 75-83 parts of dichloromethane to re-dissolve, then transferring to a reaction bottle containing 0.8-1.2 parts of silica and 60-68 parts of dichloromethane, continuing to stir and react at room temperature under argon protection for 5-24h; (A3), filtering with a microporous filter membrane, washing with deionized water and anhydrous ethanol respectively for 1-3 times, and then vacuum drying to obtain ferrocene-based modified silica.

5. The method for preparing a high solid content self-emulsifying organosilicon defoamer based on ferrocene group modification according to claim 4, characterized in that: The silica is hydrophilic fumed silica dried at 80°C under vacuum for 12h; the vacuum drying treatment is at 60°C under vacuum for 3-12h; the pore size of the microporous filter membrane is 0.22 microns.

6. The method for preparing a high solid content self-emulsifying organosilicon defoamer based on ferrocene group modification according to claim 1, characterized in that, The preparation method of the redox-responsive modified polysiloxane comprises the following steps: (B1), under argon protection, mixing 10.0 parts of hydrogen-containing silicone oil, 0.220-0.353 parts of ferrocene formic acid allyl ester ACOFc, 0.360-0.720 parts of allyl polyoxyethylene methyl-terminated polyether APEG and 0.020 parts of platinum catalyst by weight, stirring at room temperature for 20-30min to obtain a mixed liquid; (B2), heating the mixed solution to 75-85°C for 2-6h, and then increasing the temperature to 135-145°C for 1-2h to obtain a red-brown viscous liquid with HLB value of 4-7, which is the redox-responsive modified polysiloxane.

7. The method for preparing a high solid content self-emulsifying organosilicon defoamer based on ferrocene group modification according to claim 6, characterized in that: The hydrogen-containing silicone oil has hydrogen content of 0.15-0.25wt%; and the Pt concentration of the platinum catalyst is 1000ppm.

8. The preparation method of high solid content self-emulsifying organosilicon defoamer based on ferrocene group modification according to claim 1, characterized in that: The preparation method of the polymer steric stabilizer comprises the following steps: (C1), mixing 11-13 parts of polyethylene glycol 6000 and 85-100 parts of toluene by weight, heating to reflux under argon protection, and separating water through a water trap; (C2), adding 0.90-0.98 parts of isophorone diisocyanate and 0.030-0.050 parts of organic tin catalyst to the reaction system, increasing the temperature to 75-85°C, and constant temperature reaction for 2-4h; (C3), adding single-end hydroxyl silicone oil to the reaction system, continuing to react at 75-85°C for 2-4h, then increasing the temperature to 88-93°C for 1-2h, pouring it into 60-90°C 220-240 parts of petroleum ether, stirring to precipitate the polymer, standing for 5-10h, and then filtering to obtain the precipitate; (C4), dissolving the precipitate with 23-30 parts of toluene, and repeating the precipitation in 220-240 parts of petroleum ether once, and then vacuum drying to obtain white solid with HLB value of 11-15, which is the polymer steric stabilizer.

9. The method for preparing a high solid content self-emulsifying silicone defoamer based on ferrocene group modification according to claim 8, characterized in that: The organic tin catalyst is dibutyltin dilaurate; the molar ratio of the single-end hydroxyl silicone oil to polyethylene glycol 6000 is 4.2-4.8:2; and the vacuum drying treatment is at 40°C for 48h.

10. A high solids self-emulsifying silicone defoamer based on ferrocene-based modification, characterized by: The preparation method of the high solid content self-emulsifying organosilicon defoaming agent based on ferrocene group modified is adopted. The preparation method of the high solid content self-emulsifying organosilicon defoaming agent based on ferrocene group modified is adopted.

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