Preparation method and application of polar group-containing modified silicone polymer and defoaming agent

Abstract

The application discloses a preparation method and application of a defoaming agent containing a polar group-containing modified organosilicon polymer shown in formula 3 or formula 4. The polarized modified organosilicon can effectively disperse and anchor the hydrophilic silicon dioxide particles, on the one hand, significantly improving the dispersibility and compatibility of the defoaming agent in the aqueous system; on the other hand, the silicon dioxide can be firmly anchored, and the dispersion stability of the silicon dioxide in the system is greatly enhanced. The prepared polarized organosilicon can effectively chelate the silicon dioxide and has excellent dispersion in water, and the defoaming agent has outstanding defoaming and bubble inhibiting performance, especially the stability in the aqueous system and the compatibility with the resin.

Description

Technical Field

[0001] This invention relates to the field of defoamer technology, specifically to a method for preparing and applying a modified organosilicon polymer containing polar groups and a defoamer. Background Technology

[0002] Application systems containing surfactants or surfactant polymers, such as water-based coatings, water-based inks, water-based cutting fluids, and water-based cleaning fluids, all experience various foaming problems during application. Defoamers are a relatively effective way to control foam and achieve the required application and usage conditions.

[0003] Commonly used defoamers include mineral oil-based, organic polymer-based, organosilicon-based, and various compound systems. Among them, organosilicon defoamers, with their excellent surface activity, chemical inertness, and thermal stability, have become important additives for suppressing and eliminating foam in industrial production, and are widely used in water-based coatings, inks, adhesives, textile printing and dyeing, and wastewater treatment.

[0004] Patent CN111760334A discloses a method for preparing an organosilicon defoamer, comprising silicone oil, fumed silica, emulsifier, and an aqueous solution of sodium carboxymethyl cellulose. The silicone oil used is a quaternary ammonium salt-modified polyether silicone oil, and the fumed silica is a hydrophobic fumed silica. Organosilicon defoamers typically use surface-hydrophobically modified fumed silica (also known as silica) to enhance the defoaming rate and defoaming efficiency. However, this often brings disadvantages: firstly, surface-hydrophobically modified fumed silica is relatively expensive; secondly, surface-hydrophobically modified fumed silica typically has relatively weak polarity, resulting in weak bonding with the organosilicon polymer portion. During application, the two parts are prone to separation, leading to decreased efficiency, poor dispersibility, and in severe cases, surface aggregation, significantly affecting performance.

[0005] Therefore, effectively improving the bonding force between the two parts has always been an important problem that urgently needs to be solved in this field.

[0006] Patent CN116457393A discloses a method for preparing a polyether-modified organosilicon polymer for use as an antifoaming agent. This patent involves reacting polyoxyethylene / polyoxypropylene with a hydrogen-containing organosilicon polymer, followed by mixing with fumed silica to form an antifoaming composition for use in metalworking oils, providing long-lasting defoaming efficiency. This invention utilizes hydrophilic fumed silica.

[0007] According to the inventor's long-term experimental findings:

[0008] Polyether-modified organosilicon polymers have difficulty forming a strong anchoring effect on both hydrophilic and hydrophobic fumed silica. This is especially true in some low-viscosity metal cutting fluids and water treatment applications, where repeated circulation processes are required. This can easily lead to the separation of fumed silica from organosilicon polymers, resulting in their accumulation on the surface of the processing fluid and affecting its performance.

[0009] Water-based coatings are widely used in industries such as construction and furniture. However, during the preparation, mixing, spraying, and curing processes, these systems are highly susceptible to bubble formation due to factors such as shear forces, differences in interfacial tension, and changes in environmental humidity. Residual bubbles can lead to defects in the coating, such as pinholes, craters, and fisheyes, which not only affect the appearance and gloss but also reduce the coating's adhesion and corrosion resistance, severely limiting the product yield. Therefore, highly efficient and compatible defoamers are crucial additives for ensuring the quality of this system.

[0010] This invention aims to address the shortcomings of existing silicone defoamers by providing a defoamer composition that achieves self-emulsification and greater stability during use. Through molecular structure design, succinic anhydride groups with both hydrophilic and anchoring functions are introduced to construct a silicone-fumed silica composite system that combines self-dispersion, stable anchoring, and highly efficient defoaming, thereby systematically solving the aforementioned technical problems. Summary of the Invention

[0011] To overcome the shortcomings of the prior art, the present invention provides a method for preparing a polarized modified organosilicon polymer and an antifoaming agent, as well as their applications.

[0012] By introducing polar anhydride groups, efficient dispersion and anchoring of hydrophilic fumed silica particles can be achieved, resulting in the preparation of high-performance organosilicon defoamers with self-emulsification capabilities and excellent stability.

[0013] The defoamer described in this invention, through innovative molecular structure, effectively overcomes the problems of poor stability, difficulty in balancing defoaming efficiency and system compatibility, and complex emulsification processes caused by the reliance on external emulsifiers in traditional silicone defoamers. Simultaneously, this invention significantly improves the dispersion stability of fumed silica in the defoamer.

[0014] Unlike existing technologies, this invention uses an alkenyl succinic anhydride-containing compound as the hydrophilic functional component and a hydrogen-containing polysiloxane as the hydrophobic carrier, constructing a polymer structure with both hydrophilic and hydrophobic segments through chemical bonds. The succinic anhydride groups not only endow the defoamer with excellent dispersibility and compatibility in aqueous systems but also effectively anchor fumed silica particles, enhancing their long-term stable dispersion in the system. The synergistic effect of stable fumed silica and polysiloxane gives this defoamer excellent defoaming and foam-suppressing properties.

[0015] The defoamer prepared by the organosilicon polymer of this invention maintains good compatibility with aqueous systems even at high addition levels. In coating applications, it is less prone to surface defects such as pinholes and fisheyes, making it suitable for industrial applications with stringent appearance requirements. When used in low-viscosity metalworking fluids, it does not exhibit surface aggregation and demonstrates excellent compatibility and defoaming efficiency even after prolonged use.

[0016] To achieve the objectives of this invention, the technical solution adopted is as follows:

[0017] A modified organosilicon polymer containing polar groups, wherein the organosilicon polymer is shown in Formula 3 or Formula 4 below:

[0018]

[0019] Equation 3, wherein R is Ph or C4H9;

[0020]

[0021] In Equation 3 and Equation 4, R is Ph or C4H9.

[0022] A method for preparing a polar-group-modified organosilicon polymer includes the following steps:

[0023] The single-terminal hydrogen-containing polysiloxane shown in Formula 1 is added dropwise to the compound of alkenyl succinic anhydride shown in product E1 over 2-3 hours at 110-150°C. The molar ratio of the compound of alkenyl succinic anhydride (product E1) and the single-terminal hydrogen-containing polysiloxane (Formula 1) added to the reaction is 1.1:2 to 1.2:2. At the same time, 0.01-0.03% chloroplatinic acid catalyst is added. After the addition is complete, the reaction is carried out at 110-150°C for 5 hours.

[0024]

[0025] Formula 1;

[0026] The specific reaction is shown in Reaction Formula 1 below:

[0027]

[0028] Reaction 1.

[0029] A method for preparing a polar-group-modified organosilicon polymer includes the following steps:

[0030] The single-terminated hydrogen-containing polysiloxane shown in Formula 2 is added dropwise to the compound of alkenyl succinic anhydride shown in product E2 at 110-150°C for 2-3 hours. The molar ratio of the compound of alkenyl succinic anhydride (product E2) and the single-terminated hydrogen-containing polysiloxane (Formula 2) added to the reaction is 1.1:1 to 1.2:1. At the same time, 0.01-0.03% chloroplatinic acid catalyst is added. After the dropwise addition is completed, the reaction is carried out at 110-150°C for 6 hours.

[0031]

[0032] Formula 2;

[0033] The specific reaction is shown in equation 2 below:

[0034]

[0035] Reaction 2.

[0036] In a preferred embodiment of the present invention, the alkenyl succinic anhydride product E1 is prepared by the following method (Tetrahedron. Vol. 52. No. 39. pp. 12799-12814, 1996), specifically as shown in reaction formula 3 below:

[0037]

[0038] Reaction 3.

[0039] In a preferred embodiment of the present invention, the aldehyde compound in reaction formula 3 is n-pentanal or benzaldehyde.

[0040] In a preferred embodiment of the present invention, the alkenyl succinic anhydride product E2 is prepared by the following method (Tetrahedron. Vol. 52. No. 39. pp. 12799-12814, 1996), specifically as shown in reaction formula 4 below:

[0041]

[0042] Reaction 4.

[0043] In a preferred embodiment of the present invention, the aldehyde compound in reaction formula 4 is n-pentanal or benzaldehyde.

[0044] A method for preparing an antifoaming agent of an organosilicon polymer modified with polar groups includes the following steps:

[0045] The defoamer is obtained by mixing the polar-group modified organosilicon polymer, fumed silica and triethanolamine as shown in Formula 3 or Formula 4 in a certain proportion and reacting them at 130-150 degrees for 6-8 hours.

[0046] The amount of fumed silica added is 2-5% of the molar number of the polar-group-modified organosilicon polymer shown in Formula 3 or Formula 4.

[0047] The amount of fumed silica added is 0.2-0.5% of the mass of the organosilicon polymer with polar groups modified as shown in Formula 3 or Formula 4.

[0048] An application of an antifoaming agent, said application being for use as an antifoaming agent in water-based high-gloss varnish systems or as an antifoaming agent in water-based metal cutting fluid systems.

[0049] In a preferred embodiment of the present invention, the waterborne varnish system is a waterborne single-component polyacrylic resin system.

[0050] The beneficial effects of this invention are as follows:

[0051] The organosilicon defoamer prepared by this invention contains succinic anhydride groups, which endow it with excellent aqueous dispersibility and system compatibility, making it suitable for a variety of aqueous application systems.

[0052] The present invention maintains outstanding compatibility and high defoaming efficiency in both single-end hydrogen-containing polysiloxane and side-end hydrogen-containing polysiloxane structures.

[0053] The succinic anhydride group in this invention can effectively anchor fumed silica, significantly improving its dispersion and storage stability in defoamers.

[0054] The defoamer prepared by this invention remains well compatible with water-based varnish systems even under high addition levels, and does not cause surface defects such as pinholes, making it widely applicable. Detailed Implementation

[0055] In long-term research on existing silicone defoamers, the inventors have found that most of these products generally employ an external emulsifier to disperse the silicone polymer in water, followed by emulsification using specialized equipment. Defoamers produced in this way often struggle to balance storage stability, defoaming efficiency, and system compatibility. Furthermore, silicone defoamers containing fumed silica commonly exhibit separation between the fumed silica and the silicone polymer during storage, affecting the durability and uniformity of product performance.

[0056] To overcome the aforementioned shortcomings, the inventors, through systematic experimental research, confirmed that polymers (Formula 3) can be prepared by reacting alkenyl succinic anhydride compounds (product E1) with single-ended hydrogen-containing polysiloxanes (Formula 1); similarly, polymers (Formula 4) can be obtained by reacting alkenyl succinic anhydride compounds (product E2) with side-ended hydrogen-containing polysiloxanes (Formula 2). These two types of organosilicon polymers containing succinic anhydride groups exhibit significantly improved dispersibility in aqueous media, while effectively anchoring fumed silica, enhancing its dispersion stability and storage stability in the system, thereby effectively alleviating or avoiding stratification. When applied to systems such as waterborne varnishes, they demonstrate excellent defoaming effects and good compatibility.

[0057] The advantages of the present invention will be further described below with reference to embodiments and comparative examples:

[0058] Preparation method of alkenyl succinic anhydride compound E1:

[0059] In a 1L four-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, under nitrogen protection, 0.1 mol of potassium tert-butoxide was added to 400 mL of tert-butanol solvent. The mixture was stirred and heated to reflux until the solid was completely dissolved. Then, a mixture of 0.5 mol of aldehyde compound, 0.55 mol of diethyl succinate, and 200 mL of tert-butanol from the dropping funnel was added dropwise to the reaction flask over 1.5 hours. The reaction was then refluxed for another 3 hours. The pH of the crude reaction mixture was adjusted to 2 using hydrochloric acid, and the tert-butanol was removed under reduced pressure. The residue was dissolved in dichloromethane and extracted three times with sodium bicarbonate solution. The organic extract was evaporated to dryness to give product A.

[0060] In a 1L four-necked flask equipped with a stirrer, Dean-Stark apparatus, and thermometer, 0.5 mol of reactant A, 12.5 mL of concentrated sulfuric acid, 250 mL of ethanol, and 150 mL of toluene were added. The mixture was heated to reflux for 16 hours, and 30 mL of the azeotrope was collected. Then, 50 mL of toluene was added, and the mixture was heated to reflux for another 18 hours. 250 mL of sodium bicarbonate aqueous solution was added, and toluene and ethanol were removed under reduced pressure. The remaining portion was extracted three times with dichloromethane. The organic extract was dried using magnesium sulfate, filtered, and then evaporated to dryness to obtain product B.

[0061] In a 1L four-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, under nitrogen protection, 0.1 mol of potassium tert-butoxide was added to 400 mL of tert-butanol solvent. The mixture was stirred and heated to reflux until the solid was completely dissolved. Then, a mixture of 0.5 mol of product B, 0.55 mol of the aldehyde compound, and 200 mL of tert-butanol from the dropping funnel was added dropwise to the reaction flask over 1.5 hours. The reaction was then refluxed for another 3 hours. The pH of the crude reaction mixture was adjusted to 2 using hydrochloric acid, and the tert-butanol was removed under reduced pressure. The residue was dissolved in dichloromethane and extracted three times with sodium bicarbonate solution. The organic extract was dried over magnesium sulfate, filtered, and evaporated to dryness to obtain product C.

[0062] In a 1L four-necked flask equipped with a stirrer, reflux condenser, and thermometer, 0.4 mol of product C and 400 mL of (2 mol / L) sodium hydroxide solution were added, and the mixture was stirred and heated under reflux for 12 hours. The pH of the reaction solution was adjusted to 2 with hydrochloric acid, and the solution was extracted three times with dichloromethane. The organic extract was dried over magnesium sulfate, filtered, and evaporated to dryness to obtain product D1.

[0063] In a 500 mL four-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 0.2 mol of product D1 was added. Then, at -78 °C, 20 eq of trifluoroacetic anhydride was added dropwise to the reaction flask over 1 hour. The mixture was then heated to reflux and reacted for 3 hours. Residual trifluoroacetic anhydride and trifluoroacetic acid were removed by distillation. The crude product was recrystallized in ethyl acetate to give alkenyl succinic anhydride product E1, as detailed in reaction formula 3.

[0064]

[0065] Reaction 3.

[0066] Preparation method of alkenyl succinic anhydride compound E2:

[0067] In a 1L four-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, under nitrogen protection, 0.1 mol of potassium tert-butoxide was added to 400 mL of tert-butanol solvent. The mixture was stirred and heated to reflux until the solid was completely dissolved. Then, a mixture of 0.5 mol of aldehyde compound, 0.55 mol of diethyl succinate, and 200 mL of tert-butanol from the dropping funnel was added dropwise to the reaction flask over 1.5 hours. The reaction was then refluxed for another 3 hours. The pH of the crude reaction mixture was adjusted to 2 using hydrochloric acid, and the tert-butanol was removed under reduced pressure. The residue was dissolved in dichloromethane and extracted three times with sodium bicarbonate solution. The organic extract was evaporated to dryness to give product A.

[0068] In a 1L four-necked flask equipped with a stirrer, reflux condenser, and thermometer, 0.4 mol of product A and 400 mL of (2 mol / L) sodium hydroxide solution were added, and the mixture was stirred and heated under reflux for 12 hours. The pH of the reaction solution was adjusted to 2 with hydrochloric acid, and the solution was extracted three times with dichloromethane. The organic extract was dried over magnesium sulfate, filtered, and evaporated to dryness to obtain product D2.

[0069] In a 500 mL four-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 0.2 mol of product D2 was added. Then, at -78 °C, 20 eq of trifluoroacetic anhydride was added dropwise to the reaction flask over 1 hour. The mixture was then heated to reflux and reacted for 3 hours. Residual trifluoroacetic anhydride and trifluoroacetic acid were removed by distillation. The crude product was recrystallized in ethyl acetate to give alkenyl succinic anhydride product E2, as detailed in reaction formula 4.

[0070]

[0071] Reaction 4.

[0072] Example 1: Preparation of alkenyl succinic anhydride (3E,4E)-3,4-dipentyl dihydrofuran-2,5-dione E1-1:

[0073] According to the above method for preparing alkenyl succinic anhydride compound E1, wherein the aldehyde compound in reaction formula 3 is n-pentanal, compound (3E,4E)-3,4-dipentyl dihydrofuran-2,5-dione E1-1 is obtained.

[0074]

[0075] Example 2: Preparation of alkenyl succinic anhydride 3,4-bis((E)-benzylene)dihydrofuran-2,5-dione E1-2:

[0076] According to the above method for preparing alkenyl succinic anhydride compound E1, wherein the aldehyde compound in reaction formula 3 is benzaldehyde, compound 3,4-bis((E)-benzyl)dihydrofuran-2,5-dione E1-2 is obtained.

[0077]

[0078] Example 3: Preparation of alkenyl succinic anhydride (E)-3-pentyl dihydrofuran-2,5-dione E2-1:

[0079] According to the above method for preparing alkenyl succinic anhydride compound E2, wherein the aldehyde compound in reaction formula 4 is n-pentanal, compound (E)-3-pentyldihydrofuran-2,5-dione E2-1 is obtained.

[0080]

[0081] Example 4: Preparation of alkenyl succinic anhydride (E)-3-benzide dihydrofuran-2,5-dione E2-2:

[0082] According to the above method for preparing alkenyl succinic anhydride compound E2, wherein the aldehyde compound in reaction formula 4 is benzaldehyde, compound (E)-3-benzyl dihydrofuran-2,5-dione E2-2 is obtained.

[0083]

[0084] Example 5: Preparation of high-performance defoamer S1:

[0085] In a 5L three-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 236g of the alkenyl succinic anhydride (3E,4E)-3,4-dipentyl dihydrofuran-2,5-dione E1-1 prepared in Example 1 above and 0.55g of chloroplatinic acid catalyst were added, stirred, and heated to 130°C. Then, 2500g of a single-ended hydrogen-containing polysiloxane (molecular weight 1258, m=15) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150°C, and infrared detection was used until the reaction was complete. Then, 82g of silica and 8.5g of triethanolamine were added, and the reaction was carried out at 130-150°C for 6-8 hours. Heating was then stopped. Defoamer S1 was obtained.

[0086] Example 6: Preparation of high-performance defoamer S2:

[0087] The preparation method was the same as in Example 5, except that 0.83g of chloroplatinic acid catalyst was added, and 3900g of single-ended hydrogen-containing polysiloxane (molecular weight 1998, m=25) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150℃, and infrared detection was used until the reaction was finished. Then, 124g of silica and 12.5g of triethanolamine were added, and the reaction was carried out at 130-150℃ for 6-8 hours before heating was stopped. Defoamer S2 was obtained.

[0088] Example 7: Preparation of high-performance defoamer S3:

[0089] In a 5L three-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 276g of the alkenyl succinic anhydride 3,4-bis((E)-benzylene)dihydrofuran-2,5-dione E1-2 prepared in Example 2 above and 0.55g of chloroplatinic acid catalyst were added, stirred, and heated to 130°C. Then, 2500g of a single-terminated hydrogen-containing polysiloxane (molecular weight 1258, m=15) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150°C, and infrared detection was used until the reaction was complete. Then, 84g of silica and 8.5g of triethanolamine were added, and the reaction was carried out at 130-150°C for 6-8 hours. Heating was then stopped. Defoamer S3 was obtained.

[0090] Example 8: Preparation of high-performance defoamer S4:

[0091] The preparation method was the same as in Example 7, except that 0.84 g of chloroplatinic acid catalyst was added, and 3900 g of single-terminated hydrogen-containing polysiloxane (molecular weight 1998, m=25) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150°C, and infrared detection was used until the reaction was finished. Then, 125 g of silica and 12.5 g of triethanolamine were added, and the reaction was carried out at 130-150°C for 6-8 hours before heating was stopped. Defoamer S4 was obtained.

[0092] Example 9: Preparation of high-performance defoamer S5:

[0093] In a 1L three-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 168g of the alkenyl succinic anhydride (E)-3-pentyl dihydrofuran-2,5-dione E2-1 prepared in Example 3 above and 0.08g of chloroplatinic acid catalyst were added, stirred, and heated to 130°C. Then, 220g of hydrogen-containing polysiloxane (molecular weight 2242, n1=20, n2=10, H=0.45%) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150°C, and infrared detection was used until the reaction was complete. Then, 12g of silica and 1.2g of triethanolamine were added, and the reaction was carried out at 130-150°C for 6-8 hours. Heating was then stopped. Defoamer S5 was obtained.

[0094] Example 10: Preparation of high-performance defoamer S6:

[0095] The preparation method was the same as in Example 9, except that 0.1g of chloroplatinic acid catalyst was added, and 330g of hydrogen-containing polysiloxane (molecular weight 3352, n1=35, n2=10, H=0.30%) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150℃, and infrared detection was used until the reaction was finished. Then, 15g of silica and 1.5g of triethanolamine were added, and the reaction was carried out at 130-150℃ for 6-8 hours, after which heating was stopped. Defoamer S6 was obtained.

[0096] Example 11: Preparation of high-performance defoamer S7:

[0097] In a 1L three-necked flask equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 188g of the alkenyl succinic anhydride (E)-3-benzide dihydrofuran-2,5-dione E2-2 prepared in Example 4 above and 0.08g of chloroplatinic acid catalyst were added, stirred, and heated to 130°C. Then, 220g of side-containing hydrogen polysiloxane (molecular weight 2242, n1=20, n2=10, H=0.45%) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150°C, and infrared detection was used until the reaction was complete. Then, 12g of silica and 1.2g of triethanolamine were added, and the reaction was carried out at 130-150°C for 6-8 hours. Heating was then stopped. Defoamer S7 was obtained.

[0098] Comparative Example 1:

[0099] According to the preparation method of patent CN116457393A, the polyether used is methyl-terminated polyoxyethylene polyoxypropylene allyl ether (molecular weight 1850), the hydrogen-containing polysiloxane contains 0.15% hydrogen, and the fumed silica is Evonik AEROSIL 200. The mixture is homogenized using a homogenizer.

[0100] Example 12: Preparation of high-performance defoamer S8:

[0101] The preparation method was the same as in Example 11, except that 0.1g of chloroplatinic acid catalyst was added, and 330g of hydrogen-containing polysiloxane (molecular weight 3352, n1=35, n2=10, H=0.30%) was added dropwise over 4 hours. After the addition was complete, the reaction was controlled at 130-150℃, and infrared detection was used until the reaction was finished. Then, 16g of silica and 1.6g of triethanolamine were added, and the reaction was carried out at 130-150℃ for 6-8 hours, after which heating was stopped. Defoamer S8 was obtained.

[0102] Example 13:

[0103] Defoaming performance and test results of water-based one-component polyacrylic varnish system:

[0104] Examples 5-12 and two commercially available defoamers were tested for defoaming properties, foam suppression, compatibility, and the effect of defoamers on the gloss and haze value of the paint film in an aqueous single-component acrylic system.

[0105] 1) Test formula

[0106] Table 1: Polyacrylate Varnish

[0107]

[0108] 2) Defoaming and foam suppression test methods: Place the varnishes prepared with different defoamers according to the formula in Table 1 above into 200ml graduated cylinders. Use an air pump to aerate the graduated cylinders for 30 minutes and record the foam height. The higher the foam, the worse the foam suppression. Let it stand and record the time it takes for all the foam to disappear. The shorter the time, the better the defoaming effect.

[0109] 3) Compatibility test method: The varnishes prepared with different defoamers according to the formula in Table 1 above are coated on a glass plate using a 100-micron wire rod. The presence and number of pinholes are recorded. The fewer the number of pinholes, the better the compatibility.

[0110] 4) Gloss and Haze Value Test Method: For varnishes prepared with different defoamers according to the formulas in Table 1 above, a mold is made on a glass plate using a 150-micron frame-type wet film preparer. The mold is then placed in a 60℃ oven for 2 hours to dry, and then removed and allowed to cool to room temperature. The gloss and haze value are tested using a haze gloss meter. Higher gloss and lower haze value indicate a smaller impact of the defoamer on the paint film.

[0111] Table 2: Application tests of defoamers S1-S8 prepared in the examples and Comparative Example 1 in polyacrylic varnish systems

[0112]

[0113] As can be seen from the results recorded in Table 2, the defoamer of the present invention has excellent and balanced defoaming and foam-suppressing properties, as well as excellent compatibility; at the same time, it does not have a negative impact on the paint film.

[0114] Example 14:

[0115] The application of the defoamer prepared by this invention in semi-synthetic cutting fluids.

[0116] The defoaming properties, foam suppression properties, and compatibility of Examples 5-12 and two commercially available defoamers were tested in a semi-synthetic cutting fluid.

[0117] 1) Test formula

[0118] Table 3: Semi-synthetic cutting fluid test formulations

[0119]

[0120] 2) Defoaming and foam suppression test methods: Cutting fluids prepared with different defoamers according to the formula in Table 1 above were placed in 2000ml graduated cylinders, and then 900ml of deionized water was added for dilution. The test was conducted using a metalworking fluid stability tester. A filter barrel with a 300-mesh filter screen (10cm in diameter, circular) was installed. The circulation time was set to 8 hours, the temperature to 50℃, and the pressure to 2.1P (5.72L / min). The foam height was recorded. The higher the foam, the worse the foam suppression. The time it took for all the foam to disappear was recorded after standing. The shorter the time, the better the defoaming effect.

[0121] 3) Compatibility assessment: Set a circulation time of 48 hours, then remove the filter tank, rinse the filter screen with clean water, and observe the precipitation of the defoamer. Rating 1-5:

[0122] 0 points: No separation or oily substance observed online.

[0123] 1 point: Less than 2% separation on the surface, no oily substance.

[0124] 2 points: Less than 5% separation on the surface, no oily substance.

[0125] 3 points: Less than 10% of the sample separated online, with a small amount of oily substance.

[0126] 4 points: Less than 10-25% of the substance separated online, consisting of oily matter and a small amount of particles.

[0127] 5 points: More than 25% of the sample separated online, containing a large amount of particulate and oily substances.

[0128] Table 4: Application Tests of Examples S1-S7 and Comparative Examples in Cutting Fluid

[0129]

[0130] The preferred embodiments of the present invention have been described above, and the design concept and implementation method of the present invention have been described in detail, further verifying the universality and effectiveness of the present invention. Therefore, any technical solution that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of the prior art should be within the scope of protection defined by the claims.

Claims

1. A modified organosilicon polymer containing polar groups, characterized in that, The organosilicon polymer is shown in Formula 3 or Formula 4 below: Equation 3, wherein R is Ph or C4H9; In Equation 3 and Equation 4, R is Ph or C4H9.

2. The method for preparing a polar-group-modified organosilicon polymer as described in claim 1, characterized in that, Includes the following steps: The single-terminal hydrogen-containing polysiloxane shown in Formula 1 is added dropwise to the compound of alkenyl succinic anhydride shown in product E1 over 2-3 hours at 110-150°C. The molar ratio of the compound of alkenyl succinic anhydride (product E1) and the single-terminal hydrogen-containing polysiloxane (Formula 1) added to the reaction is 1.1:2 to 1.2:

2. At the same time, 0.01-0.03% chloroplatinic acid catalyst is added. After the addition is complete, the reaction is carried out at 110-150°C to obtain the organosilicon polymer with polar groups modified as shown in Formula 3. Formula 1; The specific reaction is shown in Reaction Formula 1 below: Reaction 1.

3. The method for preparing a polar-group-modified organosilicon polymer as described in claim 1, characterized in that, Includes the following steps: The single-terminal hydrogen-containing polysiloxane shown in Formula 2 is added dropwise to the compound of alkenyl succinic anhydride shown in product E2 at 110-150℃ for 2-3 hours. The molar ratio of the compound of alkenyl succinic anhydride (product E2) and the single-terminal hydrogen-containing polysiloxane (Formula 2) added to the reaction is 1.1:1 to 1.2:

1. At the same time, 0.01-0.03% chloroplatinic acid catalyst is added. After the dropwise addition is completed, the reaction is carried out at 110-150℃ to obtain the organosilicon polymer with polar groups modified as shown in Formula 4. Formula 2; The specific reaction is shown in equation 2 below: Reaction 2.

4. The method for preparing a polar-group-modified organosilicon polymer as described in claim 2, characterized in that, The alkenyl succinic anhydride product E1 is prepared by the following method, as shown in reaction formula 3 below: Reaction 3.

5. The method for preparing a polar-group-modified organosilicon polymer as described in claim 3, characterized in that, The alkenyl succinic anhydride product E2 is prepared by the following method, as shown in reaction formula 4 below: Reaction 4.

6. A method for preparing a polar-group-modified organosilicon polymer as described in claim 2 or 3, characterized in that, The aldehyde compound in reaction formula 3 or reaction formula 4 is n-pentanal or benzaldehyde.

7. A method for preparing an antifoaming agent of a polar-group-modified organosilicon polymer as described in claim 1, characterized in that, Includes the following steps: The defoamer is obtained by mixing the polar-group modified organosilicon polymer, fumed silica and triethanolamine as shown in Formula 3 or Formula 4 in a certain proportion and reacting them at 130-150 degrees for 6-8 hours. The amount of fumed silica added is 2-5% of the molar number of the polar-group-modified organosilicon polymer shown in Formula 3 or Formula 4. The amount of fumed silica added is 0.2-0.5% of the mass of the organosilicon polymer with polar groups modified as shown in Formula 3 or Formula 4.

8. An application of the defoamer as described in claim 7, characterized in that, The application is for use as a defoamer in water-based high-gloss varnish systems or as a defoamer in water-based metal cutting fluid systems.

9. An application of the defoamer as described in claim 8, characterized in that, The water-based varnish system is a water-based single-component polyacrylic acid resin system.

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