A defoaming agent, its preparation method and application

Abstract

The application provides a defoaming agent and a preparation method and application thereof. According to weight parts, the defoaming agent comprises modified animal and plant essence silicone oil 15-30 parts, seaweed nitro humic acid 20-30 parts, modified polyhexamethyl disiloxane 15-25 parts, a surfactant 2-5 parts, a milk melting agent 8-19 parts, a dispersing agent 2-6 parts, a thickening agent 1-3 parts, a fixing agent 1-2 parts and deionized water 150-250 parts. The defoaming agent provided by the application improves the stability and durability of defoaming, is suitable for various water-based and oil-based systems, and is conducive to large-scale popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, and relates to an antifoaming agent, and more particularly to an antifoaming agent, its preparation method and application. Background Technology

[0002] In the field of water treatment, foam problems have always plagued technical researchers, including foam in the initial commissioning stage, surfactant foam, impact foam, peroxide foam, and foam generated by adding non-oxidizing bactericides in circulating water treatment. Therefore, eliminating foam in the water treatment process is essential.

[0003] Physical methods for eliminating foam mainly include placing baffles or filters, mechanical stirring, electrostatic discharge, freezing, heating, steam, radiation, high-speed centrifugation, pressurization and depressurization, high-frequency vibration, instantaneous discharge, and ultrasound. These methods all, to varying degrees, promote the gas permeation rate at both ends of the liquid film and the drainage of the foam, making the stabilizing factor of the foam less than the decay factor, thus gradually reducing the amount of foam. However, a common drawback of these methods is that their application is highly dependent on environmental factors and their defoaming rate is not high.

[0004] From a chemical perspective, methods for eliminating foam mainly include chemical reaction methods and the addition of defoamers. Chemical reaction methods involve adding reagents to cause a chemical reaction between the foaming agent and the foaming agent, generating substances insoluble in water. This reduces the concentration of surfactants in the liquid film, promoting foam breakdown. However, this method has drawbacks such as uncertain foaming agent composition and the generation of insoluble substances that can damage the system equipment. Therefore, the most widely used defoaming method in various industries today is the addition of defoamers. The biggest advantage of this method is its high foam-breaking efficiency and ease of use; therefore, finding suitable and efficient defoamers is crucial.

[0005] CN108744612A discloses a mineral oil-based defoamer and its preparation method. The defoamer's raw material formulation contains hydroxyl-terminated polydimethylsiloxane, hydrophobic silica, and hydrocarbon oil. The mineral oil-based defoamer prepared by this invention can not only suppress harmful foams generated during polymerization, stripping, and filling in the production process of styrene-butadiene latex, but also effectively control oil shrinkage, pinholes, and fisheyes in subsequent coatings, thus suppressing foam. However, the addition of hydrophobic particles adversely affects the stability of the defoamer, and the defoamer is only suitable for oil-based systems, exhibiting poor defoaming effect in water-based systems, lacking versatility, and its foam suppression durability still needs further improvement.

[0006] Therefore, how to provide a defoamer and its preparation method, improve the stability and durability of defoaming, and broaden its application scenarios has become an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a defoamer, its preparation method and application. The defoamer improves the stability and durability of defoaming, is suitable for various water and oil systems, and is conducive to large-scale promotion and application.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides an antifoaming agent, which, by weight parts, comprises the following components:

[0010]

[0011] The modified plant and animal-derived silicone oil comprises 15-30 parts by weight, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts; the seaweed nitrohumic acid comprises 20-30 parts by weight, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts; and the modified polyhexamethyldisiloxane comprises... The alkane is present in parts by weight of 15-25, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 parts; the surfactant is present in parts by weight of 2-5, for example, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, or 5 parts; and the melt emulsion is present in parts by weight of 8-19, for example, ... The quantities are 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 parts by weight. The dispersant has a weight of 2-6 parts, for example, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 parts. The thickener has a weight of 1-3 parts, for example, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, or 3 parts. The fixative... The weight percentage is 1-2 parts, for example, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, or 2 parts. The weight percentage of the deionized water is 150-250 parts, for example, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, 210 parts, 220 parts, 230 parts, 240 parts, or 250 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0012] In this invention, the modified plant and animal extracted silicone oil can be any one or a combination of at least two of the following: polydiorganosiloxane-polyether block copolymer modified silicone oil, alkyl ether polyether silicone oil, epoxy polyether silicone oil, amino polyether block silicone oil, glyceryl ether silicone oil, phosphate ester silicone oil, glycosyl polyether silicone oil, or betaine-based silicone oil.

[0013] In this invention, the seaweed nitrohumic acid is specifically nitrohumic acid formed by the decomposition and transformation of seaweed by microorganisms. Its basic structure is an aromatic ring and an alicyclic ring, and the ring is connected with functional groups such as carboxyl, hydroxyl, carbonyl, quinone, and methoxy groups. As long as it is seaweed nitrohumic acid, it is applicable to this invention. Therefore, its specific composition is not particularly limited here.

[0014] In this invention, the modified polyhexamethyldisiloxane is a copolymer of hexamethyldisiloxane modified with alkyl or epoxy groups and polyether or alcohol hydroxyl groups to replace a portion of ethylene glycol. It can significantly improve properties such as tear strength, abrasion resistance, and heat resistance, with a degree of polymerization of 1000-3000.

[0015] In the defoamer provided by this invention, the modified plant and animal-derived silicone oil enhances its foam-suppressing durability, making it resistant to both high and low temperatures; the seaweed nitrohumic acid balances the pH value and improves adsorption and durability; and the modified polyhexamethyldisiloxane improves properties such as tear strength, abrasion resistance, and heat resistance.

[0016] The defoamer provided by this invention uses modified plant and animal-derived silicone oil, seaweed nitrohumic acid, and modified polyhexamethylene disiloxane as its main components, which meets the requirements of green environmental protection. At the same time, it is compounded with specific amounts of surfactants, emulsifiers, dispersants, thickeners, and fixatives. Through the synergistic effect between the components, it fully destroys the surface tension and double-layer electron interaction of the foam. It is suitable for various water and oil systems, has strong versatility, improves the stability and durability of defoaming, and is conducive to large-scale promotion and application.

[0017] Preferably, the surfactant comprises any one or a combination of at least two of 2,4,7,9-tetramethyl-5-decyn-4,7-diol, natural plant surface oils, fatty alcohol polyoxyethylene ethers, or 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol. Typical but non-limiting combinations include combinations of 2,4,7,9-tetramethyl-5-decyn-4,7-diol and natural plant surface oils, combinations of natural plant surface oils and fatty alcohol polyoxyethylene ethers, combinations of fatty alcohol polyoxyethylene ethers and 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol, combinations of 2,4,7,9-tetramethyl-5-decyn-4,7-diol, natural plant surface oils and fatty alcohol polyoxyethylene ethers, or combinations of natural plant surface oils, fatty alcohol polyoxyethylene ethers and 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol.

[0018] Preferably, the melt emulsion comprises any one or a combination of at least two of polysilane-modified polyoxyethylene sorbitan fatty acid ester, methylglucose sesquistearate, sorbitan oleate, or PEG-10 polydimethylsiloxane. Typical but non-limiting combinations include a combination of polysilane-modified polyoxyethylene sorbitan fatty acid ester and methylglucose sesquistearate, a combination of methylglucose sesquistearate and sorbitan oleate, a combination of sorbitan oleate and PEG-10 polydimethylsiloxane, a combination of polysilane-modified polyoxyethylene sorbitan fatty acid ester, methylglucose sesquistearate and sorbitan oleate, or a combination of methylglucose sesquistearate, sorbitan oleate and PEG-10 polydimethylsiloxane.

[0019] In this invention, the polysilane-modified polyoxyethylene sorbitan fatty acid ester is a substance obtained by silane modification and polymerization of polyoxyethylene sorbitan fatty acid ester (TweenX), with a degree of polymerization of 1000-3000.

[0020] Preferably, the dispersant comprises any one or a combination of at least two of poly(meth)acrylic acid derivatives, polyoxyethylene derivatives, alkylolamides, polyol monofatty acid esters, alkylamine oxides, or N-alkylpyrrolidone. Typical but non-limiting combinations include combinations of poly(meth)acrylic acid derivatives and polyoxyethylene derivatives, combinations of polyoxyethylene derivatives and alkylolamides, combinations of alkylolamides and polyol monofatty acid esters, combinations of polyol monofatty acid esters and alkylamine oxides, combinations of alkylamine oxides and N-alkylpyrrolidones, combinations of poly(meth)acrylic acid derivatives, polyoxyethylene derivatives, and alkylolamides, combinations of polyoxyethylene derivatives, alkylolamides, and polyol monofatty acid esters, combinations of alkylolamides, polyol monofatty acid esters, and alkylamine oxides, or combinations of polyol monofatty acid esters, alkylamine oxides, and N-alkylpyrrolidones.

[0021] In this invention, the degree of polymerization of the poly(meth)acrylic acid derivative is 1000-2500, and can specifically be poly(meth)acrylic acid methyl ester and / or polyrotaxane; the degree of polymerization of the polyoxyethylene derivative is 1000-2900, and can specifically be any one or a combination of at least two of ethoxylated glycerol ricinoleate, beet oil monoethanolamide polyoxyethylene, or corn germ oil monoethanolamide polyoxyethylene.

[0022] Preferably, the thickener comprises any one or a combination of at least two of polysaccharide derivatives, starch derivatives, or alginate. Typical but non-limiting combinations include combinations of polysaccharide derivatives and starch derivatives, combinations of starch derivatives and alginate, combinations of polysaccharide derivatives and alginate, or combinations of polysaccharide derivatives, starch derivatives, and alginate.

[0023] In this invention, the polysaccharide derivative can be any one or a combination of at least two of cellulose ether, trehalose, or cyclodextrin, and the starch derivative can be carboxymethyl starch and / or maltodextrin.

[0024] Preferably, the fixative comprises any one or a combination of at least two of acetylenic glycol, sodium ricinoleate, phosphite, epoxidized soybean oil, or hindered phenol. Typical but non-limiting combinations include combinations of acetylenic glycol and sodium ricinoleate, sodium ricinoleate and phosphite, phosphite and epoxidized soybean oil, epoxidized soybean oil and hindered phenol, acetylenic glycol, sodium ricinoleate and phosphite, sodium ricinoleate, phosphite and epoxidized soybean oil, or phosphite, epoxidized soybean oil and hindered phenol.

[0025] In a second aspect, the present invention provides a method for preparing the defoamer as described in the first aspect, the method comprising the following steps:

[0026] (1) Mix modified plant and animal refined silicone oil, seaweed nitrohumic acid and surfactant and heat and stir to obtain the first intermediate;

[0027] (2) The modified polyhexamethyldisiloxane and the melt emulsion were mixed and heated and stirred to obtain the second intermediate;

[0028] (3) Mix the first intermediate, the second intermediate and the dispersant and stir at room temperature to obtain the third intermediate;

[0029] (4) Mix the thickener, fixative, deionized water and third intermediate and stir at room temperature to obtain the defoamer.

[0030] The preparation method provided by the present invention involves stepwise mixing and stirring of each component, limiting whether heating is required during each stirring process, and determining the heating temperature of each step based on the critical point of each component's reaction, ultimately obtaining a stable and effective product.

[0031] Preferably, the heating and stirring temperature in step (1) is 50-60℃, for example, it can be 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃ or 60℃, and the time is 30-50min, for example, it can be 30min, 32min, 34min, 36min, 38min, 40min, 42min, 44min, 46min, 48min or 50min, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0032] Preferably, the heating and stirring temperature in step (2) is 55-65℃, for example, it can be 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, 61℃, 62℃, 63℃, 64℃ or 66℃, and the time is 40-60min, for example, it can be 40min, 42min, 44min, 46min, 48min, 50min, 52min, 54min, 56min, 58min or 60min, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0033] Preferably, the temperature of the stirring at room temperature in step (3) is 10-30℃, for example, it can be 10℃, 12℃, 14℃, 16℃, 18℃, 20℃, 22℃, 24℃, 26℃, 28℃ or 30℃, and the time is 60-120min, for example, it can be 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min, 100min, 105min, 110min, 115min or 120min, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0034] Preferably, the temperature of the stirring at room temperature in step (4) is 10-30℃, for example, it can be 10℃, 12℃, 14℃, 16℃, 18℃, 20℃, 22℃, 24℃, 26℃, 28℃ or 30℃, and the time is 60-120min, for example, it can be 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min, 100min, 105min, 110min, 115min or 120min, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0035] Thirdly, the present invention provides an application of the defoamer as described in the first aspect, wherein the defoamer is used for defoaming treatment of aqueous or oily systems, and the dilution dosage is ≤100ppm, for example, it can be 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm or 100ppm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0036] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] The defoamer provided by this invention uses modified plant and animal-derived silicone oil, seaweed nitrohumic acid, and modified polyhexamethylene disiloxane as its main components, which meets the requirements of green environmental protection. At the same time, it is compounded with specific amounts of surfactants, emulsifiers, dispersants, thickeners, and fixatives. Through the synergistic effect between the components, it fully destroys the surface tension and double-layer electron interaction of the foam. It is suitable for various water and oil systems, has strong versatility, improves the stability and durability of defoaming, and is conducive to large-scale promotion and application. Detailed Implementation

[0039] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0040] Example 1

[0041] This embodiment provides an antifoaming agent and its preparation method. The antifoaming agent comprises the following components by weight:

[0042]

[0043]

[0044] In this embodiment, the degree of polymerization of the polydiorganosiloxane-polyether block copolymer modified silicone oil is 1260; the degree of polymerization of the modified polyhexamethyldisiloxane is 1250; the degree of polymerization of the polysilane modified polyoxyethylene sorbitan fatty acid ester is 1650; and the degree of polymerization of the poly(meth)acrylate is 1230.

[0045] In this embodiment, the preparation method includes the following steps:

[0046] (1) Mix polydiorganosiloxane-polyether block copolymer modified silicone oil, seaweed nitrohumic acid and 2,4,7,9-tetramethyl-5-decyn-4,7-diol, heat and stir at 55°C for 40 min to obtain the first intermediate.

[0047] (2) Mixed modified polyhexamethyldisiloxane and polysilane modified polyoxyethylene dehydrated sorbitan fatty acid ester, heated and stirred at 60°C for 50 min to obtain the second intermediate;

[0048] (3) Mix the first intermediate, the second intermediate and poly(meth)acrylate and stir at room temperature (25°C) for 90 min to obtain the third intermediate;

[0049] (4) Mix cyclodextrin, acetylacetonate, deionized water and the third intermediate and stir at room temperature (25°C) for 90 min to obtain the defoamer.

[0050] Example 2

[0051] This embodiment provides an antifoaming agent and its preparation method. The antifoaming agent comprises the following components by weight:

[0052]

[0053]

[0054] In this embodiment, the degree of polymerization of the alkyl ether polyether silicone oil is 1130; the degree of polymerization of the modified polyhexamethyldisiloxane is 1110; and the degree of polymerization of the corn germ oil monoethanolamide polyoxyethylene is 1050.

[0055] In this embodiment, the preparation method includes the following steps:

[0056] (1) Mix alkyl ether polyether silicone oil, seaweed nitrohumic acid and 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol, heat and stir at 50°C for 50 min to obtain the first intermediate;

[0057] (2) Mix modified polyhexamethyldisiloxane and methylglucose sesquistearate, heat and stir at 55°C for 60 min to obtain the second intermediate;

[0058] (3) Mix the first intermediate, the second intermediate and corn germ oil monoethanolamide polyoxyethylene and stir at room temperature (10℃) for 120 min to obtain the third intermediate;

[0059] (4) Mix maltodextrin, sodium ricinoleate, deionized water and the third intermediate and stir at room temperature (10°C) for 120 min to obtain the defoamer.

[0060] Example 3

[0061] This embodiment provides an antifoaming agent and its preparation method. The antifoaming agent comprises the following components by weight:

[0062]

[0063]

[0064] In this embodiment, the degree of polymerization of the epoxy polyether silicone oil is 1000; the degree of polymerization of the modified polyhexamethyldisiloxane is 1290; and the degree of polymerization of the fatty alcohol polyoxyethylene ether is 1199.

[0065] In this embodiment, the preparation method includes the following steps:

[0066] (1) Mix epoxy polyether silicone oil, seaweed nitrohumic acid and fatty alcohol polyoxyethylene ether, heat and stir at 60°C for 30 min to obtain the first intermediate;

[0067] (2) Mix modified polyhexamethyldisiloxane and sorbitan oleate, heat and stir at 65°C for 40 min to obtain the second intermediate;

[0068] (3) Mix the first intermediate, the second intermediate and the alkylolamide and stir at room temperature (30°C) for 60 min to obtain the third intermediate;

[0069] (4) Mix seaweed oil, phosphite, deionized water and the third intermediate and stir at room temperature (30°C) for 60 minutes to obtain the defoamer.

[0070] Example 4

[0071] This embodiment provides an antifoaming agent and its preparation method. Except for replacing poly(meth)methyl acrylate with an equal mass of N-alkylpyrrolidone, the other steps and conditions are the same as in Example 1, so they will not be described in detail here.

[0072] Example 5

[0073] This embodiment provides an antifoaming agent and its preparation method. Except for replacing the acetylenic diol with an equal mass of epoxidized soybean oil, the other steps and conditions are the same as in Example 1, so they will not be described in detail here.

[0074] Comparative Example 1

[0075] This comparative example provides an antifoaming agent and its preparation method. Except for changing the weight parts of polydiorganosiloxane-polyether block copolymer modified silicone oil to 10 parts, the weight parts of seaweed nitrohumic acid to 35 parts, and the weight parts of modified polyhexamethyldisiloxane to 10 parts, the other steps and conditions are the same as in Example 1, so they will not be described in detail here.

[0076] Comparative Example 2

[0077] This comparative example provides an antifoaming agent and its preparation method. Except for replacing the polydiorganosiloxane-polyether block copolymer modified silicone oil with an equal mass of methylphenyl silicone oil, the other steps and conditions are the same as in Example 1, so they will not be described in detail here.

[0078] Comparative Example 3

[0079] This comparative example provides an antifoaming agent and its preparation method. Except for the absence of seaweed nitrohumic acid, the other steps and conditions are the same as in Example 1, so they will not be described in detail here.

[0080] Comparative Example 4

[0081] This comparative example provides an antifoaming agent and its preparation method. Except for the absence of modified polyhexamethyldisiloxane, the other steps and conditions are the same as in Example 1, and therefore will not be repeated here.

[0082] Comparative Example 5

[0083] This comparative example provides an antifoaming agent and its preparation method. Except for mixing all the components and heating and stirring at 55°C for 120 min, the other steps and conditions are the same as in Example 1, so they will not be described in detail here.

[0084] Performance testing

[0085] The defoaming performance (foam residue rate) of the defoamers obtained in Examples 1-5 and Comparative Examples 1-5 were determined according to the provisions of 4.6 in HG / T 4783-2014. The test conditions of the circulating bubbler are shown in Table 1 below.

[0086] Table 1

[0087] Test temperature / ℃ 30±1 <![CDATA[Flow rate / (m 3 / h)]]> 0.48 Sample addition amount / μL 10

[0088] The defoaming performance test results of the defoamers obtained in Examples 1-5 and Comparative Examples 1-5 are shown in Table 2 below.

[0089] Table 2

[0090] Example 1 <2％ Example 2 <5％ Example 3 <1％ Example 4 <6％ Example 5 <7％ Comparative Example 1 <6％ Comparative Example 2 <5％ Comparative Example 3 <10％ Comparative Example 4 <11％ Comparative Example 5 <9％

[0091] Therefore, the defoamer provided by this invention uses modified plant and animal-derived silicone oil, seaweed nitrohumic acid, and modified polyhexamethylene disiloxane as its main components, which meets the requirements of green environmental protection. At the same time, it is compounded with specific amounts of surfactants, emulsifiers, dispersants, thickeners, and fixatives. Through the synergistic effect between the components, it fully destroys the surface tension and double-layer electron interaction of the foam. It is suitable for various water and oil systems, has strong versatility, improves the stability and durability of defoaming, and is conducive to large-scale promotion and application.

[0092] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A defoamer for defoaming treatment of aqueous or oily systems, characterized in that, The defoamer comprises the following components by weight: 15-30 parts of modified plant and animal-derived silicone oil; 20-30 parts of seaweed nitrohumic acid; 15-25 parts of modified polyhexamethyldisiloxane; 2-5 parts surfactant; 8-19 parts of melt emulsion; Dissolving agent 2-6 parts; Thickener 1-3 parts; Fixative 1-2 parts; 150-250 parts deionized water; The modified plant and animal extract silicone oil includes any one or a combination of at least two of the following: polydiorganosiloxane-polyether block copolymer modified silicone oil, alkyl ether polyether silicone oil, epoxy polyether silicone oil, amino polyether block silicone oil, glyceryl ether silicone oil, phosphate ester silicone oil, glycosyl polyether silicone oil or betaine-based silicone oil. The seaweed nitrohumic acid mentioned is specifically nitrohumic acid formed by the decomposition and transformation of seaweed by microorganisms.

2. The defoamer according to claim 1, characterized in that, The surfactant comprises any one or a combination of at least two of 2,4,7,9-tetramethyl-5-decyn-4,7-diol, natural plant surface oils, fatty alcohol polyoxyethylene ethers, or 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol.

3. The defoamer according to claim 1, characterized in that, The melt emulsion comprises any one or a combination of at least two of the following: polysilane-modified polyoxyethylene sorbitan fatty acid ester, methylglucose sesquistearate, sorbitan oleate, or PEG-10 polydimethylsiloxane.

4. The defoamer according to claim 1, characterized in that, The dispersing agent includes any one or a combination of at least two of the following: polymethacrylic acid derivatives, polyoxyethylene derivatives, alkylolamides, polyol monofatty acid esters, alkylamine oxides, or N-alkylpyrrolidone.

5. The defoamer according to claim 1, characterized in that, The thickener includes any one or a combination of at least two of the following: polysaccharide derivatives, starch derivatives, or alginate.

6. The defoamer according to claim 1, characterized in that, The fixative includes any one or a combination of at least two of the following: argyne diol, sodium ricinoleate, phosphite ester, epoxidized soybean oil, or hindered phenol.

7. A method for preparing the defoamer according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: (1) Mix modified plant and animal refined silicone oil, seaweed nitrohumic acid and surfactant and heat and stir to obtain the first intermediate; (2) The modified polyhexamethyldisiloxane and the melt emulsion were mixed and heated and stirred to obtain the second intermediate; (3) Mix the first intermediate, the second intermediate and the dispersant and stir at room temperature to obtain the third intermediate; (4) Mix the thickener, fixative, deionized water and third intermediate and stir at room temperature to obtain the defoamer.

8. The preparation method according to claim 7, characterized in that, The heating and stirring temperature in step (1) is 50-60℃, and the time is 30-50min.

9. The preparation method according to claim 7, characterized in that, The heating and stirring in step (2) is carried out at a temperature of 55-65℃ for 40-60 minutes.

10. The preparation method according to claim 7, characterized in that, The stirring temperature in step (3) is 10-30℃ and the stirring time is 60-120min.

11. The preparation method according to claim 7, characterized in that, The stirring temperature in step (4) is 10-30℃ and the stirring time is 60-120min.

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