A preparation method of mineral oil defoamer

Abstract

The present invention aims to provide a mineral oil defoamer with balanced foam removal and suppression performance, stability, and compatibility. The present invention comprises the following steps: mixing a metal soap with a portion of the mineral oil, heating the mixture to 5-10°C above the melting point of the metal soap, and then rapidly cooling the mixture to 50-70°C to form a mixture M. The metal soap reforms a crystal lattice, thereby improving the foam removal and suppression performance of the defoamer; mixing an OPE wax with a specific acid value with a portion of the mineral oil, heating the mixture to 10-20°C above the melting point of the OPE wax, and then rapidly cooling the mixture to 50-70°C to form a mixture N. The gel properties of the OPE wax are utilized to improve the stability of the defoamer; and finally, the mixtures M and N are mixed with an emulsifier at room temperature to obtain a final mineral oil defoamer.

Description

Technical Field

[0001] The invention relates to a preparation process of a defoaming agent. The defoaming agent is a fine chemical additive. Therefore, the invention belongs to the technical field of fine chemicals. Background Art

[0002] As a fine chemical, defoaming agent is widely used in various industries. The use of defoaming agent not only needs to meet its own stability and good defoaming and antifoaming performance, but also needs to meet good compatibility with the application system. Currently, the most widely used silicone defoaming agent has excellent defoaming and antifoaming performance, but has poor compatibility with water-based systems and is prone to cause problems such as shrinkage and precipitation. Therefore, in industries with special requirements for compatibility, mineral oil defoaming agent has obvious application advantages.

[0003] In CN102489049A, metal soap is pre-mixed with an alcohol solvent to reduce the gelation phenomenon of the metal soap / hydrocarbon system and avoid stratification caused by increased viscosity of the defoaming agent. However, the introduction of the alcohol solvent will affect the defoaming and anti-foaming performance of the defoaming agent; in CN101003644A, metal soap is mixed with fatty alcohol-terminated polyether, heated, and then quickly cooled and an emulsifier is added to prepare the defoaming agent. The defoaming performance of the defoaming agent needs to be improved; in CN101991975A, fatty acid amide and metal soap are melted separately and then mixed at low temperature to improve the stability of the product. However, the presence of fatty acid amide will still destroy the gelation phenomenon of the metal soap and affect the stability of the product; CN104479439A introduces alkyl silicone oil and silicon dioxide into the mineral oil defoaming agent, which act synergistically with the metal soap to improve the defoaming and anti-foaming performance of the defoaming agent, but the compatibility of the defoaming agent needs to be improved. Summary of the Invention

[0004] The object of the present invention is to provide a mineral oil defoamer with balanced foam elimination and suppression performance, stability and compatibility. The metal soap is mixed with a portion of the mineral oil, heated to 5-10°C above the melting point of the metal soap, and then rapidly cooled to 50-70°C to form a mixture M. The metal soap reforms a crystal lattice, thereby improving the foam elimination and suppression performance of the defoamer; an OPE wax with a specific acid value is mixed with a portion of the mineral oil, heated to 10-20°C above the melting point of the OPE wax, and then rapidly cooled to 50-70°C to form a mixture N. The gel properties of the OPE wax are used to improve the stability of the defoamer; and finally, the mixture M, the mixture N and an emulsifier are mixed at room temperature to obtain a final mineral oil defoamer.

[0005] Technical solution:

[0006] The mineral oil defoamer of the present invention is composed of the following components:

[0007] A. Carrier

[0008] The carrier is a liquid organic hydrocarbon, a compound composed of carbon atoms and hydrogen atoms; it is selected from kerosene, diesel, engine oil, white oil, liquid paraffin, alkylbenzene, and naphthenic oil, and is used alone or in combination; the amount of the carrier is 60-85% of the total mass of the defoamer, and the carrier is divided into two parts, A1 and A2, and the amount of A1 accounts for 70-90% of the total mass of the carrier.

[0009] B. Defoaming substances

[0010] The defoaming substance is a fatty acid metal soap; one or more selected from magnesium salt, aluminum salt, calcium salt, and zinc salt of fatty acids, preferably one or two of monofatty acid aluminum and difatty acid aluminum mixed in any proportion, and the amount used is 3 to 20% of the total mass of the defoaming agent.

[0011] C. Defoaming agent

[0012] The defoaming auxiliary agent is oxidized polyethylene wax, the acid value of the oxidized polyethylene wax is ≥11 mgKOH.g-1, and the dosage is 3-8% of the total mass of the defoaming agent.

[0013] D. Emulsifier

[0014] The emulsifier is a nonionic surfactant, which is selected from fatty alcohol polyoxyethylene ether, oleic acid polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxyethylene fatty amine compound, polyoxyethylene sorbitan monolaurate (Tween-20), polyoxyethylene sorbitan monopalmitate (Tween-40), polyoxyethylene sorbitan monostearate (Tween-60), polyoxyethylene sorbitan monooleate (Tween-80), polyoxyethylene sorbitan trioleate (Tween-85), sorbitan monolaurate (Span-20), sorbitan monopalmitate (Span-40), sorbitan monostearate (Span-60), sorbitan monooleate (Span-80), and sorbitan trioleate (Span-85), and is used alone or in combination. The amount of the emulsifier is 3 to 20% of the amount of the defoamer.

[0015] The preparation method of mineral oil defoamer is as follows:

[0016] (1) Mix the defoaming substance B and the carrier A1 in a sealed container at the melting point B of the defoaming substance B. mp ℃ as the benchmark, heat the temperature to [B mp +(5-10)]°C, and then rapidly cooled to 50-70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M;

[0017] (2) Mix the defoaming agent C and the carrier A2 in a sealed container at the melting point C of the defoaming agent C. mp ℃ as the benchmark, heat the temperature to [Cmp +(5-10)]°C, and then rapidly cooled to 50-70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N;

[0018] (3) Mixture M, mixture N and emulsifier are mixed uniformly at room temperature to obtain the final mineral oil defoamer. DETAILED DESCRIPTION

[0019] Example 1

[0020] (1) 20g of defoaming substance magnesium stearate and 42g of carrier white oil were mixed in a sealed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp +5) °C, and then rapidly cooled to 50 °C, controlling the cooling rate to be ≥5 °C / min, to form a mixture M1;

[0021] (2) Add 3g of defoaming aid oxidized polyethylene wax (acid value is 11mgKOH.g -1 ) and 18g carrier white oil were mixed in a sealed container to obtain a defoaming agent at a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +7)°C, and then rapidly cooled to 60°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N1;

[0022] (3) Mixture M1, mixture N1 and 17 g of emulsifier fatty alcohol polyoxyethylene ether were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0023] Example 2

[0024] (1) 5g of a mixture of zinc stearate and calcium stearate, a defoaming substance, and 59.5g of carrier kerosene were mixed in a sealed container at a temperature of 100°C (100°F) and a temperature of 100°C (100°F). mp ℃ as the benchmark, heat the temperature to (B mp +6)°C, and then rapidly cooled to 55°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M2;

[0025] (2) Add 5g of defoaming aid oxidized polyethylene wax (acid value is 12mgKOH.g -1 ) and 25.5g of carrier liquid wax were mixed in a sealed container to obtain a defoaming agent at a melting point C mp ℃ as the benchmark, heat the temperature to (C mp +6) °C, then quickly cooled to 55 °C, controlling the cooling rate to ≥5 °C / min, to form a mixture N2;

[0026] (3) Mixture M2, mixture N2 and 5 g of an emulsifier mixture of oleic acid polyoxyethylene ether and castor oil polyoxyethylene ether were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0027] Example 3

[0028] (1) 10g of the defoaming substance aluminum stearate and aluminum dioctadecanoate mixture and 63g of the carrier diesel are mixed in a closed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp +7)°C, and then rapidly cooled to 60°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M3;

[0029] (2) Add 8g of defoaming aid oxidized polyethylene wax (acid value is 13mgKOH.g -1 ) and 7g of carrier liquid wax were mixed in a sealed container to obtain a defoaming agent at a melting point C mp ℃ as the benchmark, heat the temperature to (C mp +8) °C, and then rapidly cooled to 65 °C, controlling the cooling rate to be ≥5 °C / min, to form a mixture N3;

[0030] (3) Mixture M3, mixture N3 and 12 g of a mixture of emulsifiers Tween-20 and Span-20 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0031] Example 4

[0032] (1) 7g of a mixture of aluminum pentadecanoate and aluminum eicosanoate and 50g of a carrier alkylbenzene were mixed in a sealed container at a temperature of 100°C. mp ℃ as the benchmark, heat the temperature to (B mp +8)°C, and then rapidly cooled to 65°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M4;

[0033] (2) Add 8g of defoaming aid oxidized polyethylene wax (acid value is 14mgKOH.g -1 ) and 15g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +9)°C, and then rapidly cooled to 50°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N4;

[0034] (3) Mixture M4, mixture N4 and 20 g of a mixture of emulsifiers Tween-40 and Span-60 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0035] Example 5

[0036] (1) 8 g of a mixture of aluminum dibutyrate and aluminum dioctoate, a defoaming substance, and 60 g of carrier white oil were mixed in a sealed container. The mixture was heated to (Bmp+9)°C based on the melting point of the defoaming substance, Bmp°C, and then rapidly cooled to 70°C at a cooling rate of ≥5°C / min to form a mixture M5.

[0037] (2) Add 6g of defoaming aid oxidized polyethylene wax (acid value is 12mgKOH.g -1 ) and 23g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +5)°C, and then rapidly cooled to 70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N5;

[0038] (3) Mixture M5, mixture N5 and 3 g of a mixture of emulsifiers Tween-80 and Span-85 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0039] Example 6

[0040] (1) 15g of the defoaming substance aluminum linolenate and aluminum dihexadecenoate mixture and 50g of carrier white oil were mixed in a sealed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp +10)°C, and then rapidly cooled to 60°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M6;

[0041] (2) Add 5g of defoaming aid oxidized polyethylene wax (acid value is 11mgKOH.g -1 ) and 10g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +7)°C, and then rapidly cooled to 60°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N6;

[0042] (3) Mixture M6, mixture N6 and 20 g of a mixture of emulsifiers oleic acid polyoxyethylene ether and Span-40 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0043] Example 7

[0044] (1) 3g of the defoaming substance aluminum butyrate and aluminum behenate mixture and 65g of carrier white oil were mixed in a sealed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp+7)°C, and then rapidly cooled to 65°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M7;

[0045] (2) Add 4g of defoaming aid oxidized polyethylene wax (acid value is 14mgKOH.g -1 ) and 20g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +8)°C, and then rapidly cooled to 50°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N7;

[0046] (3) Mixture M7, mixture N7 and 8 g of emulsifier castor oil polyoxyethylene ether were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0047] Comparative Example 1

[0048] (1) 20g of defoaming substance magnesium stearate and 42g of carrier white oil were mixed in a sealed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to less than (B mp +5)℃, and then quickly cooled to 50℃, controlling the cooling rate to be ≥5℃ / min, to form a mixture M8; (2) 3g of defoaming auxiliary oxidized polyethylene wax (acid value is 11mgKOH.g -1 ) and 18g carrier white oil were mixed in a sealed container to obtain a defoaming agent at a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +7)°C, and then rapidly cooled to 60°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N1;

[0049] (3) Mixture M8, mixture N1 and 17 g of emulsifier fatty alcohol polyoxyethylene ether were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0050] Comparative Example 2

[0051] (1) 5g of a mixture of zinc stearate and calcium stearate, a defoaming substance, and 59.5g of carrier kerosene were mixed in a sealed container at a temperature of 100°C (100°F) and a temperature of 100°C (100°F). mp ℃ as the benchmark, heat the temperature to (B mp +6)°C, and then rapidly cooled to 55°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M2;

[0052] (2) Add 5g of defoaming aid oxidized polyethylene wax (acid value is 12mgKOH.g -1 ) and 25.5g of carrier liquid wax were mixed in a sealed container to obtain a defoaming agent at a melting point C mp℃ as the benchmark, heat the temperature to less than (C mp +6)°C, and then rapidly cooled to 55°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N8;

[0053] (3) Mixture M2, mixture N8 and 5 g of an emulsifier mixture of oleic acid polyoxyethylene ether and castor oil polyoxyethylene ether were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0054] Comparative Example 3

[0055] (1) 10g of the defoaming substance aluminum stearate and aluminum dioctadecanoate mixture and 63g of the carrier diesel are mixed in a closed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp +7)°C, and then rapidly cooled to less than 50°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M9;

[0056] (2) Add 8g of defoaming aid oxidized polyethylene wax (acid value is 13mgKOH.g -1 ) and 7g of carrier liquid wax were mixed in a sealed container to obtain a defoaming agent at a melting point C mp ℃ as the benchmark, heat the temperature to (C mp +8) °C, and then rapidly cooled to 65 °C, controlling the cooling rate to be ≥5 °C / min, to form a mixture N3;

[0057] (3) Mixture M9, mixture N3 and 12 g of a mixture of emulsifiers Tween-20 and Span-20 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0058] Comparative Example 4

[0059] (1) 7g of a mixture of aluminum pentadecanoate and aluminum eicosanoate and 50g of a carrier alkylbenzene were mixed in a sealed container at a temperature of 100°C. mp ℃ as the benchmark, heat the temperature to (B mp +8)°C, and then rapidly cooled to 65°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M4;

[0060] (2) Add 8g of defoaming aid oxidized polyethylene wax (acid value is 14mgKOH.g -1 ) and 15g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +9)°C, and then rapidly cooled to less than 50°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N9;

[0061] (3) Mixture M4, mixture N9 and 20 g of a mixture of emulsifiers Tween-40 and Span-60 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0062] Comparative Example 5

[0063] (1) 8 g of a mixture of aluminum dibutyrate and aluminum dioctoate, a defoaming substance, and 60 g of carrier white oil were mixed in a sealed container. The mixture was heated to (Bmp+9)°C based on the melting point of the defoaming substance, Bmp°C, and then cooled normally to 70°C at a cooling rate of <5°C / min to form a mixture M10.

[0064] (2) Add 6g of defoaming aid oxidized polyethylene wax (acid value is 12mgKOH.g -1 ) and 23g carrier naphthenic oil were mixed in a sealed container to a temperature of 1000 ℃ ... mp ℃ as the benchmark, heat the temperature to (C mp +5)°C, and then rapidly cooled to 70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N5;

[0065] (3) Mixture M10, mixture N5 and 3 g of a mixture of emulsifiers Tween-80 and Span-85 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0066] Comparative Example 6

[0067] (1) 15g of the defoaming substance aluminum linolenate and aluminum dihexadecenoate mixture and 50g of carrier white oil were mixed in a sealed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp +10)°C, and then rapidly cooled to 60°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M6;

[0068] (2) Add 5g of defoaming aid oxidized polyethylene wax (acid value is 11mgKOH.g -1 ) and 10g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +7)°C, and then cooled normally to 60°C at a cooling rate of less than 5°C / min to form a mixture N10;

[0069] (3) Mixture M6, mixture N10 and 20 g of a mixture of emulsifiers oleic acid polyoxyethylene ether and Span-40 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0070] Comparative Example 7

[0071] (1) 3g of the defoaming substance aluminum butyrate and aluminum behenate mixture and 65g of carrier white oil were mixed in a sealed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp +7)°C, and then rapidly cooled to 65°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M7;

[0072] (2) Add 4g of defoaming aid oxidized polyethylene wax (acid value is 10mgKOH.g -1 ) and 20g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +8)°C, and then rapidly cooled to 50°C at a cooling rate of ≥5°C / min to form a mixture N11;

[0073] (3) Mixture M7, mixture N11 and 8 g of emulsifier castor oil polyoxyethylene ether were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0074] Comparative Example 8

[0075] (1) 10g of the defoaming substance aluminum stearate and aluminum dioctadecanoate mixture and 63g of the carrier diesel are mixed in a closed container at the melting point B of the defoaming substance. mp ℃ as the benchmark, heat the temperature to (B mp +7)°C, and then rapidly cooled to greater than 70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M11;

[0076] (2) Add 8g of defoaming aid oxidized polyethylene wax (acid value is 13mgKOH.g -1 ) and 7g of carrier liquid wax were mixed in a sealed container to obtain a defoaming agent at a melting point C mp ℃ as the benchmark, heat the temperature to (C mp +8) °C, and then rapidly cooled to 65 °C, controlling the cooling rate to be ≥5 °C / min, to form a mixture N3;

[0077] (3) Mixture M11, mixture N3 and 12 g of a mixture of emulsifiers Tween-20 and Span-20 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0078] Comparative Example 9

[0079] (1) 7g of a mixture of aluminum pentadecanoate and aluminum eicosanoate and 50g of a carrier alkylbenzene were mixed in a sealed container at a temperature of 100°C. mp ℃ as the benchmark, heat the temperature to (B mp+8)°C, and then rapidly cooled to 65°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M4;

[0080] (2) Add 8g of defoaming aid oxidized polyethylene wax (acid value is 14mgKOH.g -1 ) and 15g of carrier naphthenic oil were mixed in a sealed container to obtain a defoaming agent having a melting point of C mp ℃ as the benchmark, heat the temperature to (C mp +9)°C, and then rapidly cooled to greater than 70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N12;

[0081] (3) Mixture M4, mixture N12 and 20 g of a mixture of emulsifiers Tween-40 and Span-60 were mixed uniformly at room temperature to obtain the final mineral oil defoamer.

[0082] Test Method

[0083] (1) Foam suppression performance test

[0084] Test method: Add 200g of self-prepared water-based paint to a 1000ml stainless steel cup, then add 0.3% defoaming agent, use a laboratory high-speed disperser to disperse at a speed of 1000rpm for 10 minutes, and immediately pour into a 1000ml measuring cylinder after stopping, record the weight and volume of the liquid, and calculate the specific gravity. A larger specific gravity value indicates a smaller air content, indicating that the defoaming agent has good anti-foaming performance.

[0085] (2) Compatibility test

[0086] Test method: After the high-speed dispersed paint is placed for 10 minutes, take out a small amount and place it on a glass plate. Use a 75um wet film preparation device to scrape the paint evenly at a constant speed, observe the state of the coating, and express it with a grade. The higher the grade, the better the compatibility.

[0087] Table 2 Coating grade classification

[0088]

[0089] (3) The stability of the sample was tested using a Formulaction / Turbiscan Tower / Multiple Light Scattering Stability Analyzer at a test temperature of 40°C and a sample size of 20 g. The smaller the TSI index in the test results, the better the sample stability.

[0090] The test results are as follows:

[0091] (1) Foam suppression performance test results:

[0092] Sample name Specific gravity (g / ml) Example 1 1.4568 Example 2 1.4523 Example 3 1.4536 Example 4 1.4527 Example 5 1.4530 Example 6 1.4546 Example 7 1.4512 Comparative Example 1 1.4485 Comparative Example 2 1.4416 Comparative Example 3 1.4450 Comparative Example 4 1.4433 Comparative Example 5 1.4436 Comparative Example 6 1.4464 Comparative Example 7 1.4428 Comparative Example 8 1.4448 Comparative Example 9 1.4431

[0093] (2) Compatibility test results:

[0094] Sample name Compatibility level Example 1 A5 Example 2 A5 Example 3 A5 Example 4 A5 Example 5 A5 Example 6 A5 Example 7 A5 Comparative Example 1 C3 Comparative Example 2 A4 Comparative Example 3 B4 Comparative Example 4 B3 Comparative Example 5 B4 Comparative Example 6 C3 Comparative Example 7 A4 Comparative Example 8 B4 Comparative Example 9 B3

[0095] (3) Stability test results:

[0096] Sample name TSI Index Example 1 0.7 Example 2 0.6 Example 3 0.4 Example 4 0.4 Example 5 0.5 Example 6 0.6 Example 7 0.6 Comparative Example 1 3.2 Comparative Example 2 2.7 Comparative Example 3 1.8 Comparative Example 4 1.9 Comparative Example 5 2.2 Comparative Example 6 2.6 Comparative Example 7 3.0 Comparative Example 8 1.9 Comparative Example 9 2.0

Claims

1. A method for preparing a mineral oil defoamer, comprising the following components: A. Carrier The carrier is a liquid organic hydrocarbon, a compound composed of carbon atoms and hydrogen atoms; selected from kerosene, diesel, engine oil, white oil, liquid paraffin, alkylbenzene, naphthenic oil, used alone or in combination; the amount of the carrier is 60-85% of the total mass of the defoamer, and the carrier is divided into two parts, A1 and A2, for use; B. Defoaming substances The defoaming substance is a fatty acid metal soap; one or more selected from magnesium salt, aluminum salt, calcium salt, and zinc salt of fatty acid, and the amount used is 3 to 20% of the total mass of the defoaming agent; C. Defoaming agent The defoaming aid is oxidized polyethylene wax, and the dosage is 3-8% of the total mass of the defoaming agent; D. Emulsifier The emulsifier is a nonionic surfactant selected from fatty alcohol polyoxyethylene ether, oleic acid polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxyethylene fatty amine compound, polyoxyethylene sorbitan monolaurate (Tween-20), polyoxyethylene sorbitan monopalmitate (Tween-40), polyoxyethylene sorbitan monostearate (Tween-60), polyoxyethylene sorbitan monooleate (Tween-80), polyoxyethylene sorbitan trioleate (Tween-85), sorbitan monolaurate (Span-20), sorbitan monopalmitate (Span-40), sorbitan monostearate (Span-60), sorbitan monooleate (Span-80), sorbitan trioleate (Span-85), and can be used alone or in combination. The amount of the emulsifier is 3-20% of the amount of the defoamer. The preparation method of the mineral oil defoamer is as follows: (1) Mix the defoaming substance B and the carrier A1 in a sealed container at the melting point B of the defoaming substance B. mp ℃ as the benchmark, heat the temperature to [B mp +(5-10)]°C, and then rapidly cooled to 50-70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture M; (2) Mix the defoaming agent C and the carrier A2 in a sealed container at the melting point C of the defoaming agent C. mp ℃ as the benchmark, heat the temperature to [C mp +(5-10)]°C, and then rapidly cooled to 50-70°C, controlling the cooling rate to be ≥5°C / min, to form a mixture N; (3) Mixture M, mixture N and emulsifier are mixed uniformly at room temperature to obtain the final mineral oil defoamer.

2. The method for preparing a mineral oil defoamer according to claim 1, wherein: The amount of the carrier A1 used accounts for 70-90% of the total mass of the carrier.

3. The method for preparing a mineral oil defoamer according to claim 1, wherein: The defoaming substance is one of monofatty acid aluminum and difatty acid aluminum or a mixture of the two in any proportion.

4. The method for preparing a mineral oil defoamer according to claim 1, wherein: The acid value of the oxidized polyethylene wax is ≥11 mgKOH.g-1.

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