High-shear-resistant silicone composite defoaming agent and preparation process thereof

Abstract

The present application relates to the technical field of silicone defoamer preparation, and particularly relates to a high-shear-resistant silicone composite defoamer and a preparation process thereof, which comprises, by weight, 20-60 parts of composite modified silicone, 5-20 parts of hydrophobic modified reinforcing component, 3-15 parts of composite emulsifier, 0.5-8 parts of auxiliary defoamer, 0.3-5 parts of stabilizer, 10-40 parts of carrier and 0.1-3 parts of modified auxiliary agent. The defoamer prepared by the present application has excellent high-shear resistance, and the defoaming efficiency retention rate is greater than or equal to 94.2% and up to 97.5% after high-speed shearing at 8000 r / min for 30 min, and the emulsion has no delamination, demulsification or oil floating phenomenon.

Description

Technical Field

[0001] This invention relates to the field of silicone defoamer preparation technology, specifically to a high-shear resistant silicone composite defoamer and its preparation process. Background Technology

[0002] Organosilicon defoamers, with their excellent surface activity and defoaming properties, have become core additives for controlling foam and stabilizing production processes in industries such as chemicals, coatings, textiles, and water treatment. As industrial production processes continue to upgrade, harsh conditions such as high-shear mixing, high-speed dispersion, and high-pressure fluid transportation are becoming increasingly common, placing higher demands on the shear resistance, system stability, and long-term applicability of defoamers.

[0003] Existing patent CN108690505A discloses a polyether-modified silicone defoamer and its preparation method. It uses polyether-modified silicone oil as the active component in combination with fumed silica, which has a certain defoaming effect. However, this product uses a single modified silicone oil, the component has a single function and insufficient synergistic effect, and its performance degrades significantly when facing high shear environment.

[0004] Existing patent CN110105352A discloses a composite organosilicon defoamer that uses amino-modified silicone oil and silica as a compound. However, it uses unmodified inorganic filler as a reinforcing component. The filler has poor compatibility with the organosilicon matrix, which can easily lead to uneven dispersion and system agglomeration, directly affecting the stability of the emulsion.

[0005] Existing patent CN109134206A discloses a shear-resistant silicone defoamer that uses a single emulsifier in combination with a one-step emulsification method. The emulsification effect is limited, the emulsion particles are unevenly distributed, the interfacial bonding is weak, and it is prone to stratification, demulsification, and oil floating after high-speed shearing.

[0006] Existing silicone defoamer technologies suffer from the following problems: Using a single modified silicone as the active ingredient results in limited component function and insufficient synergistic effect, leading to significant performance degradation under high shear conditions; using unmodified inorganic fillers as reinforcing components results in poor compatibility between the fillers and the silicone matrix, easily leading to uneven dispersion and system agglomeration; traditional preparation processes often employ a single emulsifier combined with a one-step emulsification method, resulting in uneven emulsion particle distribution and weak interfacial bonding, making it prone to stratification, demulsification, and oil floating after high-speed shearing; conventional processes lack constant-temperature curing and secondary shearing stages, preventing sufficient stabilization of the emulsion's internal structure, making it susceptible to precipitation and failure during long-term storage or under high-temperature environments. Summary of the Invention

[0007] The primary objective of this invention is to provide a high-shear resistant organosilicon composite defoamer and its preparation process.

[0008] A further objective of this invention is to provide a high-shear resistant organosilicon composite defoamer, comprising, by weight: 20-60 parts of composite modified organosilicon, 5-20 parts of hydrophobic modified reinforcing component, 3-15 parts of composite emulsifier, 0.5-8 parts of defoaming aid, 0.3-5 parts of stabilizer, 10-40 parts of carrier, and 0.1-3 parts of modifying agent; wherein the composite modified organosilicon is composed of amino-epoxy dual-modified silicone oil and polyether modified silicone oil, the hydrophobic modified reinforcing component is composed of hydrophobic modified silica and modified zinc oxide nanoflowers, the composite emulsifier is formed by compounding nonionic emulsifier and cationic emulsifier, wherein the nonionic emulsifier is selected from fatty alcohol polyoxyethylene ether, Span 60, and Tween 80, the cationic emulsifier is selected from hexadecyltrimethylammonium chloride and dodecyl dimethyl benzyl ammonium chloride, and the modifying agent contains organotin catalyst and antioxidant.

[0009] Preferably, in the composite modified organosilicon, the weight ratio of amino-epoxy dual-modified silicone oil to polyether modified silicone oil is 8-40:12-20.

[0010] Preferably, in the hydrophobic modified reinforcing component, the weight ratio of hydrophobic modified silica to modified zinc oxide nanoflowers is 3-15:2-6.

[0011] Preferably, the composite emulsifier is one of the following: fatty alcohol polyoxyethylene ether and hexadecyltrimethylammonium chloride, Span 60 and dodecyl dimethyl benzyl ammonium chloride, Tween 80 and hexadecyltrimethylammonium chloride, and Tween 80 and dodecyl dimethyl benzyl ammonium chloride.

[0012] Preferably, the defoaming agent is selected from one or more of polyether polyol, tributyl phosphate, and hydrogenated vegetable oil fatty acid ester; the stabilizer is selected from one or more of hydroxypropyl cellulose, polyvinyl alcohol, and sodium carboxymethyl cellulose; and the carrier is selected from one or more of deionized water, ethylene glycol, and propylene glycol.

[0013] A preparation process for a high-shear resistant silicone composite defoamer includes the following steps:

[0014] (1) Hydrophobic modified silica was prepared by modifying silica with γ-methacryloxypropyltrimethoxysilane at a modification temperature of 80-120℃ and a reaction time of 1-3h; modified zinc oxide nanoflowers were prepared by modifying zinc oxide nanoflowers with γ-methacryloxypropyltrimethoxysilane at a modification temperature of 60-80℃ and a reaction time of 2-4h; the two materials were mixed to prepare a hydrophobic modified reinforcing component.

[0015] (2) Mix amino-epoxy dual-modified silicone oil with polyether modified silicone oil, add organotin catalyst to react, the reaction temperature is 60-90℃, the reaction time is 1-2.5h, and composite modified organosilicon is obtained.

[0016] (3) The carrier is mixed and dissolved with the composite emulsifier, stabilizer and modifier to prepare a pre-dispersion;

[0017] (4) The composite modified organosilicon was added to the pre-dispersion liquid and emulsified to obtain a primary emulsion. The hydrophobic modified reinforcing component was added in batches and emulsified to obtain a secondary emulsion.

[0018] (5) Heat the secondary emulsion to 70-90℃ and keep it at that temperature for 2-4 hours for constant temperature maturation, stirring at 300-500 r / min;

[0019] (6) After cooling the matured emulsion to 30-50℃, perform a second shearing treatment with a shearing speed of 4000-6000 r / min and a shearing time of 20-40 min;

[0020] (7) After cooling and filtering, a high-shear resistant organosilicon composite defoamer is obtained.

[0021] Preferably, in step (1), the stirring speed for modifying silica is 1500-3000 r / min; the stirring speed for modifying zinc oxide nanoflowers is 1500-3000 r / min; the mixing speed for the two materials is 2000-4000 r / min, and the mixing time is 30-60 min.

[0022] Preferably, the stirring speed in step (2) is 800-1500 r / min.

[0023] Preferably, in step (4), the primary emulsification stirring speed is 1500-3000 r / min, the emulsification time is 30-60 min, the hydrophobic modification and reinforcing component is added in 2-4 times, and the stirring is carried out for 10-20 min after each addition, and the secondary emulsification temperature is 50-70℃.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. The defoamer prepared by this invention has excellent high shear resistance. After high-speed shearing at 8000r / min for 30min, the defoaming efficiency retention rate is ≥94.2%, and the maximum is 97.5%. The emulsion does not exhibit stratification, demulsification, or oil floating phenomena.

[0026] 2. The composite modified organosilicon of this invention has the combined ability of rapid defoaming and long-term foam suppression through the synergistic effect of amino-epoxy crosslinking and polyether grafting. The defoaming rate is ≥97.0%, with a maximum of 99.2%, and the foam suppression time is ≥110 min, with a maximum of 170 min.

[0027] 3. The hydrophobic modified reinforcing component of this invention has excellent compatibility with the organosilicon matrix. After silane modification, the silica and zinc oxide nanoflowers are uniformly dispersed in the matrix, effectively enhancing the structural strength and shear resistance of the emulsion.

[0028] 4. The constant temperature curing and secondary shearing process of this invention makes the emulsion structure fully stable and the particles fine and uniform. After the product is stored at room temperature for 6 months and at 80℃ for 72 hours, the defoaming efficiency is maintained at ≥96.5%, and there is no layering, sedimentation or discoloration. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention constructs a four-level synergistic system through innovative component compounding and optimized preparation process, which includes synergistic active host, reinforcement of reinforcing components, stabilization of emulsion system, and solidification of process structure. This system enables the organosilicon composite defoamer to achieve high shear resistance, efficient defoaming and foam suppression, and long-term storage stability.

[0031] At the active host level, the amino-epoxy dual-modified silicone oil molecular chain contains both amino (-NH2) and epoxy groups, while the polyether-modified silicone oil molecular chain contains polyether segments. Under the action of an organotin catalyst, the amino and epoxy groups in the amino-epoxy dual-modified silicone oil undergo a ring-opening reaction to form a cross-linked network structure; simultaneously, some epoxy groups undergo etherification with the terminal hydroxyl groups in the polyether-modified silicone oil, grafting polyether segments into the cross-linked network. The resulting composite modified organosilicon combines the high surface activity and rapid defoaming ability of amino-modified silicone oil, the shear-resistant framework of the epoxy cross-linked structure, and the hydrophilic dispersibility of the polyether segments. These three factors work synergistically to enable the defoamer to spread rapidly at the gas-liquid interface and provide long-lasting foam suppression.

[0032] At the reinforcing component level, after hydrophobic modification with KH570 silane coupling agent, the surface of silica changes from hydrophilic to hydrophobic, significantly improving its compatibility with the organosilicon matrix. It can then be uniformly dispersed in the matrix and form a physical reinforcing network, enhancing the strength of the emulsion structure. Zinc oxide nanoflowers possess a three-dimensional flower-like hierarchical structure with a large specific surface area. After silane modification, they become both hydrophobic and oleophilic. Their petal-like lamellar structure forms a multi-level barrier within the organosilicon matrix, effectively blocking the transmission of shear forces. Simultaneously, the porous structure of the nanoflowers can adsorb and anchor organosilicon molecules, reducing molecular chain slippage and desorption under high shear. The particle reinforcement of silica and the structural barrier of zinc oxide nanoflowers complement each other, synergistically enhancing the shear resistance of the system.

[0033] At the emulsification system level, nonionic and cationic emulsifiers are combined to form composite emulsifiers. Nonionic emulsifiers provide steric hindrance to prevent emulsion particles from agglomerating, while cationic emulsifiers form a charged double layer on the surface of emulsion particles, providing electrostatic repulsion. The dual stabilizing mechanism of steric hindrance and electrostatic repulsion makes it difficult for emulsion particles to aggregate or separate under high-speed shearing.

[0034] At the process structure solidification level, isothermal curing allows for full cross-linking and solidification of the interfacial film between emulsion particles, and thorough fusion of all components, forming a structurally stable emulsion system. Secondary shearing further refines the emulsion particles, resulting in a more uniform particle size distribution and enhancing the kinetic stability of the emulsion. The combination of these two processes ensures a sufficiently stable internal structure of the emulsion, maintaining stable performance even after high shearing.

[0035] Raw material source and specifications:

[0036] Amino-epoxy dual-modified silicone oil: amino content 0.2-0.5%, epoxy equivalent 800-1500g / eq, viscosity (25℃) 1500-4000mPa·s, Jinan Guobiao Silicone Oil Chemical Co., Ltd.

[0037] Polyether-modified silicone oil: polyether content 30-50%, HLB value 8-14, viscosity (25℃) 800-2500mPa·s, Jinan Guobiao Silicone Oil Chemical Co., Ltd.

[0038] Silica (fumed silica): Specific surface area 200±25m² 2 / g, native particle size 7-40nm, Evonik Degussa Aerosil 200;

[0039] Zinc oxide nanoflowers: three-dimensional flower-like hierarchical structure, specific surface area 15-30 m² 2 / g, petal thickness 20-50nm, overall particle size 0.5-3um, Nanjing Xianfeng Nanomaterials Technology Co., Ltd.;

[0040] γ-Methacryloxypropyltrimethoxysilane (KH570): Purity ≥97%, Nanjing Shuguang Silane Chemical Co., Ltd.;

[0041] Dibutyltin dilaurate (organotin catalyst): purity ≥95%, tin content 18.5-19.5%, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0042] Antioxidant 1010: Purity ≥98%, BASF Irganox 1010;

[0043] Fatty alcohol polyoxyethylene ether (AEO-9): HLB value 13-14, purity ≥99%, Zibo Haijie Chemical Co., Ltd.

[0044] Span 60: HLB value 4.7, purity ≥99%, Zibo Haijie Chemical Co., Ltd.;

[0045] Tween 80: HLB value 15.0, purity ≥99%, Zibo Haijie Chemical Co., Ltd.;

[0046] Hexadecyltrimethylammonium chloride (1631): 70% active ingredient content, Zibo Haijie Chemical Co., Ltd.;

[0047] Dodecyl dimethyl benzyl ammonium chloride (1227): active ingredient content 45%, Zibo Haijie Chemical Co., Ltd.;

[0048] Polyether polyols: hydroxyl value 280-320 mgKOH / g, Shandong Lanxing Dongda Chemical Co., Ltd.

[0049] Tributyl phosphate: Purity ≥99%, Sinopharm Chemical Reagent Co., Ltd.;

[0050] Hydrogenated vegetable oil fatty acid esters: iodine value ≤5, Shanghai Better Chemical Co., Ltd.;

[0051] Hydroxypropyl cellulose: viscosity 4000-6500 mPa·s (2% aqueous solution), Shandong Heda Co., Ltd.

[0052] Polyvinyl alcohol 1788: degree of alcoholysis 86-90%, viscosity 20-26 mPa·s (4% aqueous solution), Sinopec Sichuan Vinylon Plant;

[0053] Sodium carboxymethyl cellulose: viscosity 800-1200 mPa·s (2% aqueous solution), Sinopharm Chemical Reagent Co., Ltd.

[0054] Ethylene glycol: purity ≥ 99.5%, Sinopec Yangzi Petrochemical Company;

[0055] Propylene glycol: purity ≥99.5%, Sinopec Yangzi Petrochemical Company.

[0056] Example 1:

[0057] Raw material dosage: 30 parts of composite modified organosilicon, including 15 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 10 parts of hydrophobic modified reinforcing component, including 7 parts of hydrophobic modified silica and 3 parts of modified zinc oxide nanoflowers; 8 parts of composite emulsifier, including 5 parts of fatty alcohol polyoxyethylene ether and 3 parts of hexadecyltrimethylammonium chloride; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 24 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0058] Preparation process parameters:

[0059] Step 1: Preparation of the hydrophobic modified reinforcing component: Add silica to a high-speed mixer, heat to 100℃, stir at 2000 r / min, slowly add KH570 silane coupling agent (8% of silica mass), stir for 2 hours, cool to room temperature to obtain hydrophobic modified silica; mix zinc oxide nanoflowers, KH570 silane coupling agent (6% of zinc oxide nanoflower mass), and deionized water, stir at 70℃ for 3 hours, centrifuge and dry to obtain modified zinc oxide nanoflowers; mix the hydrophobic modified silica with the modified zinc oxide nanoflowers, stir at 3000 r / min for 45 minutes to obtain the hydrophobic modified reinforcing component for later use.

[0060] The second step is the preparation of the composite modified organosilicon: amino-epoxy dual-modified silicone oil and polyether modified silicone oil are added to the reaction vessel in a set ratio, heated to 75°C, dibutyltin dilaurate is added, the stirring speed is 1200 r / min, the reaction is carried out for 1.5 h, and then cooled to room temperature to obtain the composite modified organosilicon for later use.

[0061] The third step is pre-dispersion: the carrier is added to the emulsification tank, heated to 50°C, and stirred at 800 r / min. The composite emulsifier, stabilizer, and antioxidant 1010 are added in sequence and stirred for 30 min until completely dissolved to obtain a pre-dispersion.

[0062] Step 4, stepwise emulsification: Slowly add the composite modified organosilicon to the pre-dispersion liquid, adjust the stirring speed to 2000 r / min, emulsify for 45 min to obtain the primary emulsion; then add the hydrophobic modified reinforcing component to the primary emulsion in 3 parts, stirring for 15 min after each addition, and control the emulsification temperature at 60℃ to obtain the secondary emulsion.

[0063] Step 5, constant temperature maturation: heat the secondary emulsion to 80°C and keep it at that temperature for 3 hours. Reduce the stirring speed to 400 r / min to allow all components to react and blend fully.

[0064] Step 6, Secondary Shearing: Cool the matured emulsion to 40℃, adjust the stirring speed to 5000 r / min, and perform secondary shearing for 30 minutes to refine the emulsion particles. Step 7, Finished Product: Cool the emulsion after secondary shearing to room temperature, filter, and inspect to obtain a high-shear resistant silicone composite defoamer.

[0065] Example 2:

[0066] Raw material dosage: 30 parts of composite modified organosilicon, including 15 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 15 parts of hydrophobic modified reinforcing component, including 10 parts of hydrophobic modified silica and 5 parts of modified zinc oxide nanoflowers; 8 parts of composite emulsifier, including 5 parts of fatty alcohol polyoxyethylene ether and 3 parts of hexadecyltrimethylammonium chloride; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 19 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0067] Preparation process parameters: exactly the same as in Example 1.

[0068] Example 3:

[0069] Raw material dosage: 30 parts of composite modified organosilicon, including 15 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 10 parts of hydrophobic modified reinforcing component, including 7 parts of hydrophobic modified silica and 3 parts of modified zinc oxide nanoflower; 12 parts of composite emulsifier, including 7 parts of Span 60 and 5 parts of dodecyl dimethyl benzyl ammonium chloride; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 20 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0070] Preparation process parameters: Compared with Example 1, only the stirring speed of the third step of pre-dispersion was adjusted to 900 r / min, and the other process parameters were exactly the same.

[0071] Example 4:

[0072] Raw material dosage: 40 parts of composite modified organosilicon, including 25 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 10 parts of hydrophobic modified reinforcing component, including 7 parts of hydrophobic modified silica and 3 parts of modified zinc oxide nanoflowers; 8 parts of composite emulsifier, including 5 parts of fatty alcohol polyoxyethylene ether and 3 parts of hexadecyltrimethylammonium chloride; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 14 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0073] Preparation process parameters: Compared with Example 1, only the reaction temperature in the second step was adjusted to 80°C and the reaction time was adjusted to 2h, while the other process parameters were exactly the same.

[0074] Example 5:

[0075] Raw material usage: exactly the same as in Example 1.

[0076] Preparation process parameters:

[0077] The first step involves modifying precipitated silica at a temperature of 110℃, a stirring speed of 2500 r / min, and a reaction time of 1.5 h; modifying zinc oxide nanoflowers at a temperature of 75℃ and a reaction time of 2.5 h; and mixing hydrophobic modification and reinforcing components at a speed of 3500 r / min for 35 min.

[0078] The second step involves a reaction temperature of 85℃, a stirring speed of 1400 r / min, and a reaction time of 1.2 h.

[0079] The third step is to pre-dispersion at a temperature of 55℃, a stirring speed of 900 r / min, and a time of 25 min.

[0080] Step 4: Primary emulsification speed 2500 r / min, time 35 min; secondary emulsification temperature 65℃, stirring for 12 min after each addition of hydrophobic modified reinforcing component.

[0081] Step 5: Maintain a constant temperature of 85℃ for 2.5 hours and a stirring speed of 450 r / min.

[0082] Step 6: Secondary shearing temperature 45℃, rotation speed 5500r / min, time 25min.

[0083] Step 7: Finished product processing is the same as in Example 1.

[0084] Example 6:

[0085] Raw material dosage: 50 parts of composite modified organosilicon, including 30 parts of amino-epoxy dual-modified silicone oil and 20 parts of polyether modified silicone oil; 18 parts of hydrophobic modified reinforcing component, including 12 parts of hydrophobic modified silica and 6 parts of modified zinc oxide nanoflower; 14 parts of composite emulsifier, including 808 parts of Tween 80 and 6 parts of hexadecyltrimethylammonium chloride; 7 parts of defoamer, including 4 parts of hydrogenated vegetable oil fatty acid ester and 3 parts of polyether polyol; 4 parts of stabilizer, including 2 parts of hydroxypropyl cellulose and 2 parts of polyvinyl alcohol; 10 parts of carrier, including 5 parts of deionized water and 5 parts of ethylene glycol; 2.5 parts of modifying agent, including 1 part of dibutyltin dilaurate and 1.5 parts of antioxidant 1010.

[0086] Preparation process parameters: basically the same as in Example 5, except that the secondary emulsification temperature in the fourth step is adjusted to 70°C and the constant temperature curing time in the fifth step is adjusted to 4h. The remaining process steps and parameters are the same as in Example 5.

[0087] Example 7:

[0088] Raw material dosage: 25 parts of composite modified organosilicon, including 10 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 8 parts of hydrophobic modified reinforcing component, including 5 parts of hydrophobic modified silica and 3 parts of modified zinc oxide nanoflowers; 5 parts of composite emulsifier, including 3 parts of fatty alcohol polyoxyethylene ether and 2 parts of dodecyl dimethyl benzyl ammonium chloride; 1 part of defoamer (polyether polyol); 0.5 parts of stabilizer (polyvinyl alcohol); 38 parts of carrier (deionized water); 0.3 parts of modifying agent, including 0.1 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0089] Preparation process parameters: Based on Example 1, the first step of silica modification uses KH570 silane coupling agent (10% of the silica mass), the second step is a reaction temperature of 75℃, 0.1 parts of dibutyltin dilaurate are added, the stirring speed is 1000 r / min, the reaction time is 2.5 h, and the remaining process steps and parameters are the same as in Example 1.

[0090] Example 8:

[0091] Raw material dosage: 20 parts of composite modified organosilicon, including 8 parts of amino-epoxy dual-modified silicone oil and 12 parts of polyether modified silicone oil; 5 parts of hydrophobic modified reinforcing component, including 3 parts of hydrophobic modified silica and 2 parts of modified zinc oxide nanoflower; 3 parts of composite emulsifier, including 2 parts of Span 60 and 1 part of hexadecyltrimethylammonium chloride; 0.5 parts of defoamer (polyether polyol); 0.3 parts of stabilizer (polyvinyl alcohol); 40 parts of carrier (deionized water); 0.1 parts of modifying agent, including 0.05 parts of dibutyltin dilaurate and 0.05 parts of antioxidant 1010.

[0092] Preparation process parameters:

[0093] The first step involves modifying the silica at 80℃, stirring at 1500 r / min, and reacting for 3 hours; modifying the zinc oxide nanoflowers at 60℃ and reacting for 4 hours; and mixing the hydrophobic modification and reinforcing components at 2000 r / min for 60 minutes.

[0094] The second step involves a reaction temperature of 60℃, a stirring speed of 800 r / min, and a reaction time of 2 hours.

[0095] The third step is to pre-dispersion at a temperature of 40℃, a stirring speed of 500r / min, and a time of 40min.

[0096] Step 4: Primary emulsification speed 1500 r / min, time 60 min; secondary emulsification temperature 50℃, stir for 20 min after each addition.

[0097] Step 5: Maintain a constant temperature of 70℃ for 4 hours, and stir at 300 rpm.

[0098] Step 6: Secondary shearing temperature 30℃, rotation speed 4000r / min, time 40min. Step 7: Finished product processing is the same as in Example 1.

[0099] Example 9:

[0100] Raw material dosage: 60 parts of composite modified organosilicon, including 40 parts of amino-epoxy dual-modified silicone oil and 20 parts of polyether modified silicone oil; 20 parts of hydrophobic modified reinforcing component, including 15 parts of hydrophobic modified silica and 5 parts of modified zinc oxide nanoflower; 15 parts of composite emulsifier, including 10 parts of Tween 80 and 5 parts of dodecyl dimethyl benzyl ammonium chloride; 8 parts of defoamer, including 4 parts of tributyl phosphate and 4 parts of hydrogenated vegetable oil fatty acid ester; 5 parts of stabilizer, including 3 parts of sodium carboxymethyl cellulose and 2 parts of polyvinyl alcohol; 10 parts of carrier, including 6 parts of propylene glycol and 4 parts of deionized water; 3 parts of modifying agent, including 1 part of dibutyltin dilaurate and 2 parts of antioxidant 1010.

[0101] Preparation process parameters:

[0102] The first step involves modifying the silica at 120℃, stirring at 3000 r / min, and reacting for 1 hour; modifying the zinc oxide nanoflowers at 80℃ and reacting for 2 hours; and mixing the hydrophobic modification and reinforcing components at 4000 r / min for 30 minutes.

[0103] The second step involves a reaction temperature of 90℃, a stirring speed of 1500 r / min, and a reaction time of 1 hour.

[0104] The third step is to pre-dispersion at a temperature of 60℃, a stirring speed of 1000r / min, and a time of 20min.

[0105] Step 4: Primary emulsification speed 3000 r / min, time 30 min; secondary emulsification temperature 70℃, stir for 10 min after each addition.

[0106] Step 5: Maintain a constant temperature of 90℃ for 2 hours, with a stirring speed of 500 r / min.

[0107] Step 6: Secondary shearing temperature 50℃, rotation speed 6000r / min, time 20min.

[0108] Step 7: Finished product processing is the same as in Example 1.

[0109] Comparative Example 1:

[0110] Raw material dosage: 30 parts of composite modified organosilicon, including 15 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 8 parts of composite emulsifier, including 5 parts of fatty alcohol polyoxyethylene ether and 3 parts of hexadecyltrimethylammonium chloride; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 34 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0111] This comparative example lacks hydrophobic modification and reinforcing components, simulating existing technologies that do not employ reinforcing components.

[0112] Preparation process parameters: exactly the same as in Example 1.

[0113] Comparative Example 2:

[0114] Raw material dosage: 30 parts of single amino-modified silicone oil; 10 parts of hydrophobic modified reinforcing component, including 7 parts of hydrophobic modified silica and 3 parts of modified zinc oxide nanoflowers; 8 parts of composite emulsifier, including 5 parts of fatty alcohol polyoxyethylene ether and 3 parts of hexadecyltrimethylammonium chloride; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 24 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0115] This comparative example uses a single modified silicone oil, without employing composite modification.

[0116] Preparation process parameters: exactly the same as in Example 1.

[0117] Comparative Example 3:

[0118] Raw material quantities: exactly the same as in Example 1. This comparative example omits the isothermal ripening step.

[0119] Preparation process parameters: Compared with Example 1, the fifth step of constant temperature curing is deleted, and the remaining process parameters are exactly the same.

[0120] Comparative Example 4:

[0121] Raw material dosage: 15 parts of composite modified organosilicon, including 8 parts of amino-epoxy dual-modified silicone oil and 7 parts of polyether modified silicone oil; 25 parts of hydrophobic modified reinforcing component, including 15 parts of hydrophobic modified silica and 10 parts of modified zinc oxide nanoflower; 2 parts of composite emulsifier; 9 parts of defoamer; 6 parts of stabilizer; 8 parts of carrier; and 3.5 parts of modifying additives.

[0122] The amount of raw materials used in this comparative example has not been adjusted according to the applicable range of this invention.

[0123] Preparation process parameters: exactly the same as in Example 1.

[0124] Comparative Example 5:

[0125] Raw material dosage: 30 parts of composite modified organosilicon, including 15 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 10 parts of hydrophobic modified reinforcing component, including 7 parts of hydrophobic modified silica and 3 parts of modified zinc oxide nanoflower; 8 parts of single emulsifier fatty alcohol polyoxyethylene ether; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 24 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0126] This comparative example uses a single nonionic emulsifier and does not employ a composite emulsifier.

[0127] Preparation process parameters: exactly the same as in Example 1.

[0128] Comparative Example 6:

[0129] Raw material usage: exactly the same as in Example 1. This comparative example omits the secondary shearing step.

[0130] Preparation process parameters: Compared with Example 1, the sixth step of secondary shearing was deleted, and the remaining process parameters were exactly the same.

[0131] Comparative Example 7:

[0132] Raw material dosage: 30 parts of composite modified organosilicon, including 15 parts of amino-epoxy dual-modified silicone oil and 15 parts of polyether modified silicone oil; 10 parts of unmodified silica; 8 parts of composite emulsifier, including 5 parts of fatty alcohol polyoxyethylene ether and 3 parts of hexadecyltrimethylammonium chloride; 3 parts of defoamer, including 2 parts of polyether polyol and 1 part of tributyl phosphate; 1 part of stabilizer (polyvinyl alcohol); 24 parts of carrier (deionized water); 0.5 parts of modifying agent, including 0.3 parts of dibutyltin dilaurate and 0.2 parts of antioxidant 1010.

[0133] In this comparative example, unmodified silica was used to replace the hydrophobic modified reinforcing component.

[0134] Preparation process parameters: exactly the same as in Example 1.

[0135] Comparative Example 8:

[0136] Raw material usage: exactly the same as in Example 1.

[0137] This comparative example uses a one-step emulsification process instead of a pre-dispersion and stepwise emulsification process.

[0138] Preparation process parameters: Compared with Example 1, the third step of pre-dispersion and the fourth step of stepwise emulsification were deleted, and one-step emulsification was adopted (all raw materials were added to the emulsification tank at the same time for emulsification), while the remaining process parameters were exactly the same.

[0139] It should be noted that:

[0140] Tween 80 is a polyoxyethylene sorbitan monooleate, which is a pale yellow oily liquid at room temperature with an HLB value of 15.0. It has excellent water dispersibility and emulsification compatibility. When combined with the cationic emulsifier selected in this invention, it can form a stable composite emulsion system.

[0141] In this invention, the addition ratio of γ-methacryloyloxypropyltrimethoxysilane (KH570) used for powder modification is set differently according to different modification objects. Specifically, for the dry modification of fumed silica, the amount of silane coupling agent added is 6%-10% of the mass fraction of fumed silica. For the wet modification of zinc oxide nanoflowers, the amount of silane coupling agent added is 4%-8% of the mass fraction of zinc oxide nanoflowers. This ratio range can ensure that the inorganic powder surface is fully grafted with hydrophobic groups to achieve good compatibility with the organosilicon matrix, while avoiding excessive coupling agent causing self-polymerization and residue affecting the stability of the emulsion. At the same time, the system morphology of powder modification is clearly defined. Fumed silica adopts a solvent-free dry modification system, and zinc oxide nanoflowers adopt a wet modification system with deionized water as the medium. The two modification methods are designed in combination with the morphological characteristics of the powder itself to maximize the modification efficiency and effect.

[0142] The core composite emulsifier of this invention is composed of a nonionic emulsifier and a cationic emulsifier, with the overall mass ratio controlled at (1.2-2.5):1. This ratio range allows the steric hindrance effect of the nonionic emulsifier and the electrostatic repulsion effect of the cationic emulsifier to form an optimal synergy, effectively resisting the damage of emulsion particles by high shear forces. If the ratio deviates from this range, problems such as particle aggregation and emulsion stratification may occur. For the modified additive composed of organotin catalyst and antioxidant, the mass ratio of the two in the overall modified additive is 30%-60% for organotin catalyst and 40%-70% for antioxidant. The organotin catalyst mainly regulates the degree of crosslinking reaction between amino-epoxy dual-modified silicone oil and polyether modified silicone oil. Too little dosage will lead to insufficient crosslinking of silicone oil and insufficient shear strength of the skeleton, while too much dosage will easily cause an increase in side reactions and yellowing of the emulsion. The antioxidant is used to inhibit the oxidative degradation of organosilicon molecules and emulsifiers under high temperature and long-term storage. The compounding ratio can balance the reaction catalytic effect and the aging resistance of the system.

[0143] In this invention, the defoaming aid, stabilizer, and mixed carrier that can be compounded into multiple components are all set with conventional compounding ratio ranges: when the defoaming aid is selected from two or more of polyether polyol, tributyl phosphate, and hydrogenated vegetable oil fatty acid esters, there is no strict limitation on the mass ratio between the components, but the mass of a single component shall not be less than 15% of the total mass of the defoaming aid. When multiple components work together, the applicable conditions for defoaming and foam suppression can be further broadened; when the stabilizer is selected from hydroxypropyl cellulose, polyvinyl alcohol, and sodium carboxymethyl cellulose, polyvinyl alcohol shall be the main component accounting for more than 50% of the total mass of the stabilizer, and the remaining cellulose components shall assist in improving the viscosity and suspension stability of the emulsion; when the carrier is selected from ethylene glycol, propylene glycol, and deionized water, the total organic solvent shall account for 10%-50% of the carrier mass, and the freezing point and dispersion performance of the emulsion can be adjusted according to the ambient temperature.

[0144] In terms of the overall preparation process environment and operation control, all processes of this invention are carried out in a closed reaction environment under normal pressure. On the one hand, this avoids the loss of organosilicon active components due to high-temperature volatilization, and on the other hand, it prevents external dust and impurities from entering the emulsion system and causing deterioration. The overall pH value of the final product emulsion is controlled in the weakly neutral to weakly alkaline range of 6.5-8.5. This pH range can effectively prevent the modified silicone oil molecular chain from undergoing hydrolytic breakage, while ensuring the chemical stability of various emulsifiers and polymer stabilizers. This is a key condition for maintaining the long-term storage stability of the emulsion.

[0145] In addition, to avoid material agglomeration caused by excessively high local concentrations, the composite modified organosilicon and hydrophobic modified reinforcing components are fed in a uniform and slow manner, with each feeding time not less than 5 minutes. Combined with the corresponding stirring speed, this can achieve uniform mixing and emulsification of materials, further ensuring consistent product performance across batches from an operational perspective.

[0146] Performance testing and results analysis:

[0147] Test method:

[0148] (1) High shear resistance test: The defoamer was diluted to a concentration of 5% and placed in a high-speed shearing machine. It was sheared for 30 minutes at speeds of 3000 r / min, 5000 r / min and 8000 r / min respectively. After shearing, its defoaming efficiency was tested and the ratio of the defoaming efficiency after shearing to the defoaming efficiency before shearing was calculated. At the same time, it was observed whether the emulsion showed stratification, demulsification and oil floating phenomenon.

[0149] (2) Defoaming performance test: Using a Roche foam apparatus, 100 mL of 1% sodium dodecylbenzene sulfonate solution was measured, 0.1 g of defoamer was added, and the mixture was stirred evenly. The initial foam height and the foam height after 5 min were tested, and the defoaming rate was calculated.

[0150] (3) Defoaming performance test: Using a Roche foam apparatus, 100 mL of 1% sodium dodecylbenzenesulfonate solution was measured, 0.1 g of defoamer was added, and the mixture was stirred evenly. Air was continuously introduced into the solution at a rate of 50 mL / min, and the time it took for the foam to remain below 50% of its initial height was recorded.

[0151] (4) Storage stability test: The defoamer was placed in a sealed container and stored at room temperature for 6 months and at 80°C for 72 hours. The emulsion was observed to see if it would separate into layers, precipitate, or change color. At the same time, the defoaming efficiency after storage was tested and the ratio to the initial defoaming efficiency was calculated.

[0152] The test results are shown in Table 1 below:

[0153] sample 3000r / min 5000r / min 8000r / min emulsion state Defoaming rate Foam suppression time Store at room temperature for 6 months Store at 80℃ for 72 hours Defoaming efficiency ratio after storage Example 1 98.5% 97.2% 95.8% No layering, demulsification, or oil separation 98.2% 135min No layering, sedimentation, or color change No layering, sedimentation, or color change 97.8% Example 2 99.1% 98.3% 96.5% No layering, demulsification, or oil separation 98.5% 150min No layering, sedimentation, or color change No layering, sedimentation, or color change 98.2% Example 3 98.8% 97.5% 96.2% No layering, demulsification, or oil separation 98.3% 140min No layering, sedimentation, or color change No layering, sedimentation, or color change 97.9% Example 4 99.0% 98.1% 96.4% No layering, demulsification, or oil separation 98.8% 145min No layering, sedimentation, or color change No layering, sedimentation, or color change 98.1% Example 5 99.2% 98.5% 96.8% No layering, demulsification, or oil separation 98.6% 155min No layering, sedimentation, or color change No layering, sedimentation, or color change 98.3% Example 6 99.3% 98.7% 97.0% No layering, demulsification, or oil separation 99.0% 160min No layering, sedimentation, or color change No layering, sedimentation, or color change 98.5% Example 7 98.2% 96.8% 95.0% No layering, demulsification, or oil separation 97.8% 125min No layering, sedimentation, or color change No layering, sedimentation, or color change 97.2% Example 8 97.5% 95.6% 94.2% No stratification, slight oil drift 97.0% 110min No stratification, slight sedimentation No stratification, slight sedimentation 96.5% Example 9 99.5% 98.9% 97.5% No layering, demulsification, or oil separation 99.2% 170min No layering, sedimentation, or color change No layering, sedimentation, or color change 98.8% Comparative Example 1 85.3% 78.6% 65.2% Slight oil separation 90.5% 60min Slight sedimentation Obvious stratified sedimentation 82.1% Comparative Example 2 88.7% 80.2% 72.5% Slight demulsification and oil floating 92.3% 75min No stratification, slight sedimentation Layered demulsification 85.4% Comparative Example 3 89.5% 82.8% 74.3% Slight oil separation 93.1% 80min Layered sedimentation Clearly layered demulsification 86.7% Comparative Example 4 80.2% 71.5% 60.8% Clearly layered, demulsified, and oily. 88.6% 50min Severe stratification and precipitation Severe delamination, emulsion breaking, and discoloration 78.3% Comparative Example 5 87.4% 79.1% 70.6% Layered demulsification and oil separation 91.2% 70min Layered sedimentation Clearly layered demulsification 83.5% Comparative Example 6 86.8% 77.9% 68.4% Slight oil separation 90.8% 65min Slight sedimentation Layered demulsification 81.7% Comparative Example 7 84.5% 76.3% 63.7% Slight layering, emulsion breaking, and oil floating 89.7% 55min Severe stratification and precipitation Severe demulsification 80.2% Comparative Example 8 82.1% 73.4% 61.5% Clearly layered, demulsified, and oily. 88.9% 52min Severe stratification, precipitation, and discoloration Severe delamination, emulsion breaking, and discoloration 77.9%

[0154] Results analysis:

[0155] The high-shear resistant silicone composite defoamers prepared in the various embodiments of the present invention have been verified by multiple performance tests. At 8000 r / min, the defoaming efficiency retention rate is ≥94.2%, the emulsion remains stable, the defoaming rate is ≥97.0%, the foam suppression time is ≥110 min, and the defoaming efficiency ratio after storage is ≥96.5%.

[0156] Due to missing raw material components, substitution of a single raw material, deletion of core process steps, or improper raw material ratios, the product performance of each comparative example showed a significant decline. Comparative Example 1, without the addition of hydrophobic modified reinforcing components, achieved a defoaming efficiency retention rate of only 65.2% after 8000 r / min shearing, a decrease of 30.6 percentage points compared to Example 1. Comparative Example 2, using a single amino-modified silicone oil, achieved a defoaming efficiency retention rate of only 72.5% after 8000 r / min shearing. Comparative Example 5, using a single nonionic emulsifier, fatty alcohol polyoxyethylene ether, achieved a defoaming efficiency retention rate of only 70.6% after 8000 r / min shearing.

[0157] In summary, this invention employs a composite modified organosilicon and hydrophobic modified reinforcing component compound system, combined with a nonionic / cationic composite emulsifier, and incorporates optimized processes such as pre-dispersion, stepwise emulsification, constant temperature curing, and secondary shearing. The resulting organosilicon composite defoamer possesses excellent high shear resistance, high-efficiency defoaming and foam-suppressing ability, and good storage stability.

[0158] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A high-shear resistant silicone composite defoamer, characterized in that, The product comprises, by weight, 20-60 parts of composite modified organosilicon, 5-20 parts of hydrophobic modified reinforcing component, 3-15 parts of composite emulsifier, 0.5-8 parts of defoamer, 0.3-5 parts of stabilizer, 10-40 parts of carrier, and 0.1-3 parts of modifying agent; the composite modified organosilicon is composed of amino-epoxy dual-modified silicone oil and polyether modified silicone oil, the hydrophobic modified reinforcing component is composed of hydrophobic modified silica and modified zinc oxide nanoflowers, the composite emulsifier is formed by compounding nonionic emulsifier and cationic emulsifier, wherein the nonionic emulsifier is selected from fatty alcohol polyoxyethylene ether, Span 60, and Tween 80, and the cationic emulsifier is selected from hexadecyltrimethylammonium chloride and dodecyl dimethyl benzyl ammonium chloride, and the modifying agent contains organotin catalyst and antioxidant.

2. The high-shear resistant organosilicon composite defoamer according to claim 1, characterized in that, In the composite modified organosilicon, the weight ratio of amino-epoxy dual-modified silicone oil to polyether modified silicone oil is 8-40:12-20.

3. The high-shear resistant silicone composite defoamer according to claim 1, characterized in that, In the hydrophobic modified reinforcing component, the weight ratio of hydrophobic modified silica to modified zinc oxide nanoflowers is 3-15:2-6.

4. The high-shear resistant organosilicon composite defoamer according to claim 1, characterized in that, The composite emulsifier is one of the following: fatty alcohol polyoxyethylene ether and hexadecyltrimethylammonium chloride, Span 60 and dodecyl dimethyl benzyl ammonium chloride, Tween 80 and hexadecyltrimethylammonium chloride, and Tween 80 and dodecyl dimethyl benzyl ammonium chloride.

5. The high-shear resistant organosilicon composite defoamer according to claim 1, characterized in that, The defoaming agent is selected from one or more of polyether polyol, tributyl phosphate, and hydrogenated vegetable oil fatty acid ester; the stabilizer is selected from one or more of hydroxypropyl cellulose, polyvinyl alcohol, and sodium carboxymethyl cellulose; and the carrier is selected from one or more of deionized water, ethylene glycol, and propylene glycol.

6. A preparation process for a high-shear resistant silicone composite defoamer, used to prepare the high-shear resistant silicone composite defoamer according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Hydrophobic modified silica was prepared by modifying silica with γ-methacryloxypropyltrimethoxysilane at a modification temperature of 80-120℃ and a reaction time of 1-3h; modified zinc oxide nanoflowers were prepared by modifying zinc oxide nanoflowers with γ-methacryloxypropyltrimethoxysilane at a modification temperature of 60-80℃ and a reaction time of 2-4h; the two materials were mixed to prepare a hydrophobic modified reinforcing component. (2) Mix amino-epoxy dual-modified silicone oil with polyether modified silicone oil, add organotin catalyst to react, the reaction temperature is 60-90℃, the reaction time is 1-2.5h, and composite modified organosilicon is obtained. (3) The carrier is mixed and dissolved with the composite emulsifier, stabilizer and modifier to prepare a pre-dispersion; (4) The composite modified organosilicon was added to the pre-dispersion liquid and emulsified to obtain a primary emulsion. The hydrophobic modified reinforcing component was added in portions and emulsified again to obtain a secondary emulsion. (5) Heat the secondary emulsion to 70-90℃ and keep it at that temperature for 2-4 hours for constant temperature maturation, stirring at 300-500 r / min; (6) After cooling the matured emulsion to 30-50℃, perform a second shearing treatment with a shearing speed of 4000-6000 r / min and a shearing time of 20-40 min; (7) After cooling and filtering, a high-shear resistant organosilicon composite defoamer is obtained.

7. The preparation process according to claim 6, characterized in that, In step (1), the stirring speed for modifying silica is 1500-3000 r / min; the stirring speed for modifying zinc oxide nanoflowers is 1500-3000 r / min; the mixing speed for the two materials is 2000-4000 r / min, and the mixing time is 30-60 min.

8. The preparation process according to claim 6, characterized in that, In step (2), the stirring speed is 800-1500 r / min.

9. The preparation process according to claim 6, characterized in that, In step (4), the primary emulsification stirring speed is 1500-3000 r / min, and the emulsification time is 30-60 min; the hydrophobic modification and reinforcement components are added in 2-4 batches, and stirred for 10-20 min after each addition; the secondary emulsification temperature is 50-70℃.