Mineral oil antifoam agent and method for producing the same

Abstract

The present application relates to the technical field of chemical materials, and particularly relates to a mineral oil defoaming agent and a preparation method thereof, wherein, taking the total mass of the mineral oil defoaming agent as reference, the raw materials are prepared by the following components: 11%-21% of silica paste, 3%-6% of fatty acid metal soap, 3%-8% of emulsifying component, 0.1%-4% of auxiliary defoaming component, and the rest is mineral oil; the silica paste is composed of modified polysiloxane, silicone oil and hydrophobic white carbon black with a mass ratio of 7.5-12:3-5:0.5-4. The mineral oil defoaming agent provided by the present application can form silica paste by compounding modified polysiloxane and silicone oil, introduce fluorine element in the mineral oil defoaming agent, effectively reduce the surface tension by grafting polyether chain segments, improve the compounding compatibility with polycarboxylic acid water reducing agent, has good defoaming performance, has wide application range, and thus realizes the improvement of working performance and has important practical application value.

Description

Technical Field

[0001] This invention relates to the field of chemical materials technology, and in particular to a mineral oil defoamer and its preparation method. Background Technology

[0002] With the rapid development of my country's national economy and the large-scale construction of civil engineering projects, my country's construction industry has been driven towards high efficiency, high performance, and sustainability. Concrete, as a crucial civil engineering material, has a profound impact on the advancement of construction technology. The use of various types of water-reducing agents not only affects the workability of concrete in the fresh mixing stage but also improves the structure of hardened concrete at the microscopic and submicroscopic levels. This allows for the modification of concrete through the addition of water-reducing agents to meet requirements for workability, mechanical properties, and durability. Water-reducing agents enable the manufacture and construction of special concretes, such as high-flowability concrete, high-strength concrete, underwater concrete, and shotcrete. Polycarboxylate superplasticizers, due to their unique advantages of customizable molecular structure and properties, are gradually replacing lignin sulfonate superplasticizers, naphthalene-based superplasticizers, and other high-efficiency water-reducing agents, becoming the mainstream water-reducing agent in the market.

[0003] Polycarboxylate superplasticizers are concrete admixtures that reduce the amount of mixing water while maintaining a relatively constant concrete slump, and are widely used in concrete systems. During the use of polycarboxylate superplasticizers, air bubbles are often introduced due to physical mixing in the production equipment, chemical reactions between various additives, and uneven ratios of reagents and water. Furthermore, cement-based material systems introduce a large number of air bubbles during mixing and chemical reactions. Residual air bubbles can affect the strength, durability, and appearance quality of the hardened material. Therefore, the compounding process of polycarboxylate superplasticizers generally requires the addition of different amounts of defoamers to ensure their overall performance in concrete.

[0004] Mineral oil defoamers are widely used and inexpensive, attracting considerable attention. While pure mineral oil is relatively light, has low viscosity, requires large quantities, and is heat-resistant, its defoaming performance is unstable and limited. However, by adding silicone oil, especially polyether-modified polysiloxane components, defoaming and foam-suppressing properties can be significantly improved. This is mainly because the polyether segment has hydrophilic properties, while the silicone oil segment has hydrophobic properties. This combination of the strong defoaming ability of organosilicon and the good foam-suppressing effect of polyether allows it to serve as a highly efficient defoaming synergist for mineral oil defoamers, overcoming the limitation of silicone oil-containing defoamers being unsuitable for specific applications and thus broadening its application range.

[0005] Therefore, how to improve the defoamer using mineral oil as a carrier to enhance the later-stage workability of concrete is a technical problem that those skilled in the art need to solve. Summary of the Invention

[0006] To address the technical problems mentioned in the background section, this invention provides a mineral oil defoamer, which is made from raw materials comprising the following components, calculated by mass fraction based on the total mass of the mineral oil defoamer: 11%-21% silicone paste, 3%-6% fatty acid metal soap, 3%-8% emulsifying agent, 0.1%-4% defoaming aid, and the remainder being mineral oil.

[0007] The silicone paste is a composite of modified polysiloxane, silicone oil and hydrophobic silica in a mass ratio of 7.5-12:3-5:0.5-4.

[0008] Based on the above technical solution, the silicone oil is further defined as at least one of dimethyl silicone oil, hydrogen-containing silicone oil, and hydroxyl silicone oil, with a viscosity ranging from 500 to 2000 cst.

[0009] Based on the above technical solution, furthermore, the hydrophobic silica is prepared by a gas-phase method and has a specific surface area of ​​100-200 m². 2 / g.

[0010] Based on the above technical solution, the emulsifying component is further composed of two or more nonionic surfactants and / or anionic surfactants with different HLB levels.

[0011] Based on the above technical solution, the nonionic surfactant is further selected from at least one of alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ether, fatty alcohol polyoxyethylene ether, sorbitan monostearate, sorbitan monooleate, sorbitan tristearate, sorbitan trioleate; polyoxyethylene sorbitan ether stearate, sorbitan monooleate polyoxyethylene ether, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan trioleate, and castor oil polyoxyethylene ether.

[0012] The alkylphenol polyoxyethylene ether includes at least one of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, dodecylphenol polyoxyethylene ether, and dinonylphenol polyoxyethylene ether.

[0013] The fatty acid polyoxyethylene ether includes at least one of lauric acid polyoxyethylene ether, oleic acid polyoxyethylene ether, palmitic acid polyoxyethylene ether, and stearic acid polyoxyethylene ether;

[0014] The anionic surfactant includes one of carboxylates, sulfates, sulfonates, and phosphates, specifically selected from at least one of sodium dodecyl polyoxyethylene ether sulfate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium hexadecyl sulfonate, sodium hexadecylbenzene sulfonate, and sodium dodecyl diphenyl ether disulfonate.

[0015] Based on the above technical solution, the digestive aid is further composed of one or more of fatty acids, fatty alcohols, waxes and modified waxes.

[0016] Based on the above technical solution, the fatty acid metal soap is further composed of one or more of the following: magnesium salt, aluminum salt, calcium salt, and zinc salt of fatty acids.

[0017] Among them, fatty acid metal soaps are preferably fatty acid aluminum soaps; the fatty acid aluminum soaps include mono-fatty acid aluminum and di-fatty acid aluminum;

[0018] The monofatty acid aluminum includes at least one of aluminum butyrate, aluminum octanoate, aluminum tetradecanoate, aluminum pentadecanoate, aluminum hexadecanoate, aluminum heptadecanoate, aluminum octadecanoate, aluminum nonadecanoate, aluminum eicosanoate, aluminum docosanoate, aluminum triacontanate, aluminum tetradecenoate, aluminum docosanoate, and aluminum linolenate.

[0019] The preferred materials are aluminum octoate, aluminum hexadecanoate, aluminum octadecanoate, and aluminum docosanoate;

[0020] Aluminum difatty acids include at least one of aluminum dibutyrate, aluminum dioctanoate, aluminum di(tetradecanoic acid), aluminum di(pentadecanoic acid), aluminum di(hexadecanoic acid), aluminum di(heptadecanoic acid), aluminum di(octadecanoic acid), aluminum di(nonadecanoic acid), aluminum di(eicosanoic acid), aluminum di(dodecanoic acid), aluminum di(triadecanoic acid), aluminum di(hexadecenoic acid), aluminum di(octadecenoic acid), and aluminum dilinoleate;

[0021] Preferably, when the fatty acid metal soap is made of mono- or di-fatty acid aluminum, the number of carbon atoms in the fatty acid of the mono- or di-fatty acid aluminum is 4-32.

[0022] Based on the above technical solution, the mineral oil is further composed of one or more of the following: white oil, kerosene, diesel oil, engine oil, liquid wax, alkylbenzene, and naphthenic oil.

[0023] This invention provides a method for preparing any of the mineral oil defoamers described above, comprising the following preparation steps:

[0024] Preparation of modified polysiloxane: The reactor temperature is controlled at 100-130℃. Epoxy fluorosilicone oil, hydroxyl-containing polyether, and catalyst are added sequentially to the reactor. Nitrogen gas is introduced, and the mixture is stirred continuously for 2-4 hours. The modified polysiloxane is obtained by separation and purification. The mass ratio of the epoxy fluorosilicone oil, hydroxyl-containing polyether, and catalyst is 50-200:40-180:0.5-1.

[0025] Preparation of silicone paste: Control the reactor temperature at 110-150℃, add modified polysiloxane, silicone oil and hydrophobic silica to the reactor, stir continuously for 2-5 hours, and cool to room temperature to obtain silicone paste.

[0026] Preparation of mineral oil defoamer: Control the reactor temperature at 110-130℃, mix silicone paste, fatty acid metal soap, defoaming aid and mineral oil, stir at 500-1000 r / min for 0.5-1.5 h, add emulsifying ingredients, increase the speed to 1500-3000 r / min and stir for 0.5-1.5 h, cool to room temperature to obtain the mineral oil defoamer.

[0027] Based on the above technical solution, the epoxy fluorosilicone oil further has the following structural formula:

[0028]

[0029] The structural formula of the hydroxyl-containing polyether is:

[0030]

[0031] The modified polysiloxane has the following structural formula:

[0032]

[0033] Wherein, a is 0–45, b is 5–60, c is 5–60, m is 10–50, n is 10–50, and R1 is at least one of -SiO(CH3)3 or -CH2-CH2-CH2-O-CH2-C3H3O.

[0034] Based on the above technical solution, the catalyst is further selected from at least one of triethylenediamine, N-alkylmorpholine, bis(2-methyloxyethyl), ethylenediamine, triethylamine, m-phenylenediamine, and p-phenylenediamine.

[0035] The mineral oil defoamer provided by this invention has the following technical effects:

[0036] The mineral oil defoamer provided by this invention, with its modified polysiloxane containing fluorinated groups on its side chains, effectively reduces the surface tension of the mineral oil defoamer by forming a silicone paste with silicone oil and hydrophobic silica. This allows it to suppress foam formation for a longer period. Furthermore, the presence of fatty acid metal soaps and defoaming aids further enhances the defoaming and foam-suppressing properties of the mineral oil defoamer. The mineral oil-modified polysiloxane of this invention, due to the introduction of hydrophilic polyether segments, exhibits good compatibility with polycarboxylate superplasticizers, effectively improving the dispersibility of the defoaming active material during the polycarboxylate superplasticizer compounding process.

[0037] Furthermore, the mineral oil defoamer prepared by this invention has the characteristics of high temperature resistance and acid and alkali resistance, making it suitable for use under harsh conditions and expanding its application range in the compounding process of polycarboxylate superplasticizers.

[0038] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description and claims. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0040] The present invention provides the following embodiments and comparative examples:

[0041] Example 1

[0042] This embodiment provides a method for preparing modified polysiloxane A1: The reactor temperature is controlled at 110℃, and epoxy fluorosilicone oil, hydroxyl-containing polyether, and triethylenediamine are added sequentially to the reactor in a mass ratio of 70:110:0.5. Nitrogen gas is introduced, and the mixture is stirred continuously for 3 hours. The modified polysiloxane A1 is then obtained through separation and purification.

[0043] Example 2

[0044] This embodiment provides another method for preparing modified polysiloxane A2: The reactor temperature is controlled at 120℃, and epoxy fluorosilicone oil, hydroxyl-containing polyether, and triethylenediamine are added sequentially to the reactor in a mass ratio of 80:140:0.8. Nitrogen gas is introduced, and the mixture is stirred continuously for 3 hours. The modified polysiloxane A2 is then obtained through separation and purification.

[0045] Example 3

[0046] This embodiment provides a method for preparing a mineral oil defoamer: the reactor temperature is controlled at 120°C, and modified polysiloxane A1, dimethyl silicone oil, hydroxyl silicone oil and hydrophobic silica are added to the reactor in a mass ratio of 40:16:4:5. The mixture is stirred continuously for 2.5 hours and then cooled to room temperature to obtain silicone paste.

[0047] Controlling the reactor temperature at 110℃, 16 parts of silicone paste, 6 parts of aluminum eicosanoate, 0.5 parts of stearic acid, and 71.5 parts of No. 26 white oil were mixed according to the mass ratio and stirred at 500 rpm for 1 hour. 6 parts of emulsifying components (sorbitan monostearate (Span-60): polyoxyethylene sorbitan ether stearate (Tween-60) = 5:1) were added, and the stirring speed was increased to 2500 rpm for 1 hour. The mixture was then cooled to room temperature to obtain the mineral oil defoamer.

[0048] Example 4

[0049] This embodiment provides a method for preparing a mineral oil defoamer: the reactor temperature is controlled at 125°C, and modified polysiloxane A1, dimethyl silicone oil, hydroxyl silicone oil and hydrophobic silica are added to the reactor in a mass ratio of 48:14:2:9. The mixture is stirred continuously for 2.5 hours and then cooled to room temperature to obtain silicone paste.

[0050] Controlling the reactor temperature at 110℃, 14 parts of silicone paste, 4 parts of aluminum docosanoate, 1 part of stearic acid and 77 parts of No. 32 white oil were mixed according to the mass ratio and stirred at 800 / min for 1 hour. Then, 4 parts of emulsifying components (Span-80: Tween-80 = 5:1) were added, and the stirring speed was increased to 3000 / min and stirred for 1 hour. After cooling to room temperature, the mineral oil defoamer was obtained.

[0051] Example 5

[0052] This embodiment provides a method for preparing a mineral oil defoamer: the reactor temperature is controlled at 130°C, and modified polysiloxane A2, dimethyl silicone oil, hydrogen-containing silicone oil and hydrophobic silica are added to the reactor in a mass ratio of 44:9:3:5. The mixture is stirred continuously for 2.5 hours and then cooled to room temperature to obtain silicone paste.

[0053] Control the reactor temperature at 120℃. Mix 18 parts silicone paste, 4 parts aluminum stearate, 0.5 parts stearic acid and 73 parts No. 26 white oil according to the mass ratio. Stir at 500 rpm for 1 hour. Add 4.5 parts emulsifying component (Span-60: Tween-60 = 5:1), increase the speed to 2500 rpm and stir for 1 hour. Cool to room temperature to obtain mineral oil defoamer.

[0054] Example 6

[0055] This embodiment provides a method for preparing a mineral oil defoamer: the reactor temperature is controlled at 140°C, and modified polysiloxane A2, dimethyl silicone oil, hydroxyl silicone oil and hydrophobic silica are added to the reactor in a mass ratio of 50:12:1:4. The mixture is stirred continuously for 2.5 hours and then cooled to room temperature to obtain silicone paste.

[0056] Control the reactor temperature at 120℃, and mix 15 parts silicone paste, 5 parts aluminum docosanoate, 1 part stearic acid and 75 parts No. 32 white oil according to the mass ratio. Stir at 1000 / min for 1 hour, add 4 parts emulsifying component (Span-80: Tween-80 = 5:1), increase the speed to 3000 / min and stir for 1 hour. Cool to room temperature to obtain mineral oil defoamer.

[0057] The parameters provided in this embodiment are for specific reference in implementing this embodiment and are not intended to limit the concept of the present invention. Those skilled in the art can make corresponding changes to the parameters according to the inventive concept of the present invention to achieve the corresponding technical effects of the present invention.

[0058] The present invention also provides the following comparative examples:

[0059] Comparative Example 1:

[0060] Mineral oil defoamer, KZJ-X12 from Kezhijie New Materials Group Co., Ltd.

[0061] Comparative Example 2:

[0062] Based on Example 3, an equal amount of dimethyl silicone oil was used to replace the modified polysiloxane A1, and the other conditions remained the same as in Example 3, to obtain the defoamer of Comparative Example 2.

[0063] Comparative Example 3:

[0064] Based on Example 5, an equal amount of dimethyl silicone oil was used to replace the modified polysiloxane A2, and the other conditions remained the same as in Example 5, to obtain the defoamer of Comparative Example 3.

[0065] To further illustrate the performance of the mineral oil defoamer provided in the embodiments of the present invention, stability, defoaming, and foam suppression evaluation experiments were conducted on the defoamers prepared in the embodiments of the present invention and the comparative examples, as shown below:

[0066] 1. Stability evaluation:

[0067] After adjusting the concentration of the defoamer prepared above to 20%, place it in a standard colorimetric tube and let it stand for 72 hours to observe whether it will separate into layers, in order to evaluate the stability of the defoamer.

[0068] 2. Evaluation of defoaming and foam suppression:

[0069] Under normal pressure and temperature conditions, add 5g of commercially available Point-S type polycarboxylate superplasticizer mother liquor (produced by Kezhijie New Materials Group Co., Ltd.), 2g of sodium dodecylbenzenesulfonate, and 98g of saturated calcium hydroxide solution to a 1000ml graduated cylinder. Plug the graduated cylinder with a cork and shake it up and down 15 times. Record the foam height (V0) and defoaming time (t0).

[0070] Under normal pressure and temperature conditions, add 5g of commercially available Poin nt-S polycarboxylic acid (produced by Kezhijie New Materials Group Co., Ltd.) and 2g of sodium dodecylbenzenesulfonate to a 1000ml graduated cylinder, plug the graduated cylinder with a cork, shake it up and down 15 times, add 10ml of defoamer with a mass fraction of 0.05%, and record the defoaming time (t1).

[0071] Under normal pressure and temperature conditions, add 5g of commercially available Poin nt-S polycarboxylate (produced by Kezhijie New Materials Group Co., Ltd.), 2g of sodium dodecylbenzenesulfonate and 10ml of defoamer with a mass fraction of 0.05% to a 1000ml graduated cylinder, plug the graduated cylinder with a cork, and shake it up and down 15 times, and record the foam height (V1).

[0072] (t0-t1) / t0 is defined as the defoaming value, which reflects the defoaming ability of the defoamer: the higher the defoaming value, the better the defoaming ability of the defoamer.

[0073] (V0-V1) / V0 is defined as the foam suppression value, reflecting the foam suppression ability of the defoamer: the higher the foam suppression value, the better the foam suppression ability of the defoamer. The performance evaluation test results are shown in Table 1.

[0074] Table 1 Test Results

[0075] blank / 0 0 Example 3 good 0.81 0.66 Example 4 good 0.83 0.62 Example 5 good 0.82 0.64 Example 6 good 0.85 0.61 Comparative Example 1 generally 0.47 0.31 Comparative Example 2 good 0.58 0.41 Comparative Example 3 good 0.61 0.42

[0076] Through comparative testing of the above embodiments and comparative examples, Examples 3-6 showed better stability compared to Comparative Example 1, indicating that the mineral oil defoamer prepared by the technical solution of the present invention has more complete emulsification than existing defoamers. Comparative Examples 2 and 3, compared to the embodiments, did not use the modified polysiloxane provided by the present invention. Examples 3-6, compared to Comparative Examples 1-3, showed higher defoaming and foam suppression values. The modified polysiloxane introduced by the technical solution of the present invention effectively improves the defoaming and foam suppression performance of the prepared silicone defoamer, making it suitable for compound applications with polycarboxylate superplasticizers.

[0077] The mineral oil defoamer provided by this invention can form a silicone paste by modifying polysiloxane and silicone oil. By introducing fluorine into the mineral oil defoamer and grafting polyether segments, the surface tension is effectively reduced and its compatibility with polycarboxylate superplasticizer is improved. It has good defoaming and foam-suppressing performance and a wide range of applications, thereby improving its working performance.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mineral oil defoamer, characterized in that, Based on the total mass of mineral oil defoamer as a reference, and calculated according to mass fraction, it is made from raw materials including the following components: 11%-21% silicone paste, 3%-6% fatty acid metal soap, 3%-8% emulsifying ingredients, 0.1%-4% defoaming aid ingredients, and the balance being mineral oil; The silicone paste is a composite of modified polysiloxane, silicone oil, and hydrophobic silica in a mass ratio of 7.5-12:3-5:0.5-4. The preparation method of the mineral oil defoamer includes the following preparation steps: Preparation of modified polysiloxane: The reactor temperature is controlled at 100-130℃. Epoxy fluorosilicone oil, hydroxyl-containing polyether, and catalyst are added sequentially to the reactor. Nitrogen gas is introduced, and the mixture is stirred continuously for 2-4 hours. The modified polysiloxane is obtained by separation and purification. The mass ratio of the epoxy fluorosilicone oil, hydroxyl-containing polyether, and catalyst is 50-200:40-180:0.5-1. Preparation of silicone paste: Control the reactor temperature at 110-150℃, add modified polysiloxane, silicone oil and hydrophobic silica to the reactor, stir continuously for 2-5 hours, and cool to room temperature to obtain silicone paste. Preparation of mineral oil defoamer: Control the reactor temperature at 110-130℃, mix silicone paste, fatty acid metal soap, defoaming aid and mineral oil, stir at 500-1000 r / min for 0.5-1.5 h, add emulsifying ingredients, increase the speed to 1500-3000 r / min and stir for 0.5-1.5 h, cool to room temperature to obtain the mineral oil defoamer; The epoxy fluorosilicone oil has the following structural formula: ； The structural formula of the hydroxyl-containing polyether is: The modified polysiloxane has the following structural formula: Where a is 0–45, b is 5–60, c is 5–60, m is 10–50, n is 10–50, and R1 is -SiO(CH3)3; The silicone oil is at least one of dimethyl silicone oil, hydrogen-containing silicone oil, and hydroxyl silicone oil, with a viscosity range of 500-2000 cst. The hydrophobic silica was prepared by a gas-phase method and has a specific surface area of ​​100-200 m². 2 / g; The emulsifying component is composed of two or more nonionic surfactants and / or anionic surfactants with different HLB levels. The nonionic surfactant is selected from at least one of alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ether, fatty alcohol polyoxyethylene ether, sorbitan monostearate, sorbitan monooleate, sorbitan tristearate, sorbitan trioleate, polyoxyethylene sorbitan ether stearate, sorbitan monooleate polyoxyethylene ether, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan trioleate, and castor oil polyoxyethylene ether. The alkylphenol polyoxyethylene ether includes at least one of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, dodecylphenol polyoxyethylene ether, and dinonylphenol polyoxyethylene ether. The fatty acid polyoxyethylene ether includes at least one of lauric acid polyoxyethylene ether, oleic acid polyoxyethylene ether, palmitic acid polyoxyethylene ether, and stearic acid polyoxyethylene ether; The anionic surfactant is selected from at least one of sodium dodecyl polyoxyethylene ether sulfate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium hexadecyl sulfonate, sodium hexadecylbenzene sulfonate, and sodium dodecyl diphenyl ether disulfonate.

2. The mineral oil defoamer according to claim 1, characterized in that: The digestive aid is composed of one or more of fatty acids, fatty alcohols, waxes, and modified waxes.

3. The mineral oil defoamer according to claim 1, characterized in that: The fatty acid metal soap is composed of one or more of the following: magnesium salt, aluminum salt, calcium salt, and zinc salt of fatty acids.

4. The mineral oil defoamer according to claim 1, characterized in that: The mineral oil is one or more of the following: white oil, kerosene, diesel oil, engine oil, liquid wax, alkylbenzene, and naphthenic oil.

5. A method for preparing the mineral oil defoamer according to any one of claims 1-4, characterized in that, The preparation steps include the following: Preparation of modified polysiloxane: The reactor temperature is controlled at 100-130℃. Epoxy fluorosilicone oil, hydroxyl-containing polyether, and catalyst are added sequentially to the reactor. Nitrogen gas is introduced, and the mixture is stirred continuously for 2-4 hours. The modified polysiloxane is obtained by separation and purification. The mass ratio of the epoxy fluorosilicone oil, hydroxyl-containing polyether, and catalyst is 50-200:40-180:0.5-1. Preparation of silicone paste: Control the reactor temperature at 110-150℃, add modified polysiloxane, silicone oil and hydrophobic silica to the reactor, stir continuously for 2-5 hours, and cool to room temperature to obtain silicone paste. Preparation of mineral oil defoamer: Control the reactor temperature at 110-130℃, mix silicone paste, fatty acid metal soap, defoaming aid and mineral oil, stir at 500-1000 r / min for 0.5-1.5 h, add emulsifying ingredients, increase the speed to 1500-3000 r / min and stir for 0.5-1.5 h, cool to room temperature to obtain the mineral oil defoamer.

6. The method for preparing the mineral oil defoamer according to claim 5, characterized in that: The epoxy fluorosilicone oil has the following structural formula: ； The structural formula of the hydroxyl-containing polyether is: The modified polysiloxane has the following structural formula: Where a is 0–45, b is 5–60, c is 5–60, m is 10–50, n is 10–50, and R1 is -SiO(CH3)3.

7. The method for preparing the mineral oil defoamer according to claim 5, characterized in that: The catalyst is at least one of triethylenediamine, N-alkylmorpholine, bis(2-methyloxyethyl), ethylenediamine, triethylamine, m-phenylenediamine, and p-phenylenediamine.

Images