A mineral oil type defoaming agent and a method for preparing the same

Abstract

The present application relates to a kind of mineral oil type defoamer and its preparation method.The mineral oil type defoamer includes the following components, by weight: mineral oil 40~60 parts, tributyl phosphate 5~10 parts, defoaming active material 10~15 parts, defoaming adjuvant 5~10 parts, fatty acid glyceride 5~10 parts, emulsifier 1~10 parts, thickening agent 5~10 parts.The present application is compounded with hydrophobic modified titanium dioxide and ethylene bis-stearamide, which can make the product achieve excellent performance, but the stability of system can be affected by hydrophobic particles, and the above problems can be solved by further compounding fatty acid glyceride.The best ratio of defoaming adjuvant, emulsifier and thickening agent is selected.The surface tension of the mineral oil type defoamer of the present application is low, the stability is good, the defoaming speed is fast, the dispersion density is large, and the common problems of poor compatibility and harsh use conditions of mineral oil type defoamer are also solved, and it can also be used stably under high temperature, acidic conditions and the like.

Description

Technical Field

[0001] This invention relates to the field of fine chemical additives technology, specifically to a mineral oil-based defoamer and its preparation method. Background Technology

[0002] Defoamers, also known as antifoaming agents, are additives that reduce surface tension to inhibit foam formation or eliminate existing foam. Defoamers are mainly divided into three categories: mineral oil-based, organosilicon-based, and polyether-based. They are used in various fields, including daily life and industrial production, such as low-foaming laundry detergents and liquids currently on the market. Industries such as wastewater treatment, seawater desalination, and industrial fermentation also have varying degrees of demand for defoamers. Furthermore, compound defoamers can achieve different effects.

[0003] Mineral oil mainly contains hydrocarbons with a relatively small number of carbon atoms, some containing dozens of carbon atoms. Most are unsaturated hydrocarbons, including paraffin oil, alkane oil, naphthenic oil, and aromatic oil. Mineral oil defoamers are non-organosilicone defoamers, typically with mineral oil as the main component, and contain defoaming active ingredients and emulsifiers in combination.

[0004] Currently, mineral oil defoamers are mainly used in coatings and other fields. They are mainly composed of mineral oil, fatty acid metal soaps, fatty acid amides, fatty alcohols, and polyethers. Mineral oil itself has a certain defoaming effect, but its main function is as a carrier. Since it is a non-renewable resource, the use of renewable resource carriers has become a development trend. However, there are no successful cases of completely replacing mineral oil. Some products that replace it in small quantities cannot meet the performance requirements, which has become an urgent problem to be solved.

[0005] CN108744612A discloses a mineral oil 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 inhibit harmful foam 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. However, the stability of the mineral oil defoamer is affected by the addition of hydrophobic particles.

[0006] CN200510088437.6 discloses a silicone oil with three different hydrocarbons as carriers, aluminum fatty acid and silica as the main defoaming substances, which introduces some alkyl-modified silicone oils with substituents of 2 to 6 carbon atoms, which can easily cause coating defects. Summary of the Invention

[0007] This invention provides a mineral oil-based defoamer, the preparation steps of which are as follows, in parts by weight:

[0008] S1. Add 5-10 parts of tributyl phosphate, 10-15 parts of defoaming active substance, 5-10 parts of defoaming aid, and 5-10 parts of fatty acid glycerides to 40-60 parts of mineral oil, mix and stir for 20-30 minutes at a stirring speed of 300-400 rpm, then add 5-10 parts of thickener, continue stirring and heat to 70-100℃, keep warm for 1-2 hours, and cool down to 30-50℃ to obtain mixture A;

[0009] S2. Mix the above mixture A with 1 to 10 parts of emulsifier until uniform. After the mixture has cooled to room temperature, transfer it to a grinding mill and grind and disperse it with 1 to 2 mm zirconium beads for 1 to 2 hours to obtain the mineral oil-based defoamer of the present invention.

[0010] The mineral oil is at least one selected from white oil, peppermint oil, corn oil, liquid paraffin, and alkylbenzene; more preferably, the mineral oil is white oil.

[0011] The defoaming active substance is a hydrophobic particle;

[0012] The hydrophobic particles are at least one of hydrophobic silica, hydrophobic modified titanium dioxide, and ethylene bis-stearamide; more preferably, the hydrophobic particles are hydrophobic modified titanium dioxide.

[0013] More preferably, the titanium dioxide is rutile.

[0014] The defoaming active substance is a mixture of hydrophobic modified titanium dioxide and ethylene bis-stearamide in a mass ratio of (1~3):1; more preferably, the defoaming active substance is a mixture of hydrophobic modified titanium dioxide and ethylene bis-stearamide in a mass ratio of 1.5:1.

[0015] The preparation method of the hydrophobic silica is as follows, in parts by weight:

[0016] S1 feeds 10-15 parts of microsilica powder into a secondary magnetic separator to remove iron impurities, and then continues to perform high-temperature purification treatment at 700-800℃ for 1-2 hours to remove volatile substances coated on its surface.

[0017] S2. Mix the silica powder obtained in S1 with the hydrophobic agent in a certain proportion, and continue to stir at room temperature and pressure for 20 to 40 minutes at a stirring speed of 400 to 600 rpm.

[0018] S3. Place the mixture obtained in S2 into a constant temperature drying oven and activate the hydrophobicity at 180~250℃ for 1~2 h.

[0019] S4 involves ultra-fine grinding of the material obtained in S3, resulting in hydrophobic silica particles with a particle size of 1000-2000 mesh, thus obtaining the hydrophobic silica.

[0020] The hydrophobic agent is at least one of hydrocarbons, silicone oils, higher alcohols, organosilicone alcohols, and organosilicon chlorides; more preferably, the hydrophobic agent is silicone oil.

[0021] More preferably, the silicone oil is dimethyl silicone oil.

[0022] The mass ratio of the added microsilica powder to the hydrophobic agent is (10~20):1; more preferably, the mass ratio of the added microsilica powder to the hydrophobic agent is 15:1.

[0023] The defoaming agent is at least one of diethyl ether, isoamyl alcohol, polyether, triethanolamine, n-octanol, and isooctanol; more preferably, the defoaming agent is isoamyl alcohol.

[0024] The fatty acid glyceride is at least one of glyceryl monostearate, glyceryl monopalmitate, glyceryl monolaurate, and glyceryl monooleate; more preferably, the fatty acid glyceride is glyceryl monopalmitate.

[0025] More preferably, the mass ratio of the defoaming agent, emulsifier, and thickener is 4:3:4.

[0026] The emulsifier is at least one of Span 20, Span 60, and Span 80; more preferably, the emulsifier is Span 60.

[0027] The thickener is at least one of hydroxyethyl cellulose, polyvinyl alcohol, and sodium alginate; more preferably, the thickener is hydroxyethyl cellulose.

[0028] The functions of the main raw materials in this invention are described below:

[0029] Mineral oil white oil: Mineral oil-based defoamers use mineral oil as the main defoaming component. To improve effectiveness, they are sometimes mixed with substances such as metal soaps, silicone oil, and silica. Furthermore, various surfactants may be added to facilitate the diffusion of mineral oil to the foaming liquid surface or to ensure uniform dispersion of metal soaps within the mineral oil. The main functions of mineral oil white oil in mineral oil defoamers are as a carrier and to suppress foaming. 1. First, as a carrier, mineral oil white oil can bind other components in the defoamer, such as surfactants and emulsifiers, together to form a stable defoamer. Simultaneously, due to its hydrophobic properties, it helps the defoamer diffuse better on the foam surface, thus more effectively exerting its defoaming effect. 2. Second, mineral oil white oil also suppresses foaming. It can form a thin film on the foam liquid film, disrupting the integrity of the liquid film, impairing its recovery and fluidity, and ultimately causing the foam to burst. Meanwhile, mineral oil white oil has a low surface tension, which can help prevent foaming; 3. In addition, mineral oil white oil also has the advantages of low toxicity, odorless and tasteless, so it is widely used in the food, pharmaceutical and other industries.

[0030] In summary, the main function of mineral oil white oil in mineral oil defoamers is as a carrier and to suppress foam. It can bind other components together to form a stable defoamer, which then diffuses on the foam surface, disrupting the integrity and fluidity of the liquid film, thereby achieving the defoaming effect. Furthermore, it has the advantages of being low in toxicity, odorless, and tasteless, making it suitable for use in various industries.

[0031] Tributyl phosphate (TBP): The defoaming mechanism of TPP mainly relies on the alkyl chains and phosphate groups in its molecular structure. The alkyl chains are hydrophobic, interacting with hydrophobic molecules in the liquid to form a thin film. The phosphate groups are hydrophilic, interacting with water molecules in the liquid to increase the film's stability. When bubbles are present in the liquid, the alkyl chains of TPP aggregate towards the bubble surface, forming a thin film. This film effectively reduces the surface tension of the bubbles, making them less prone to diffusion and breakage. Simultaneously, the phosphate groups also interact with water molecules in the liquid, increasing the film's stability and further preventing bubble formation and diffusion. In summary, TPP breaks down foam by interfering with its stability and reducing its surface tension. It is an excellent surfactant that rapidly diffuses on the foam surface, reducing the foam's elastic modulus and making it more susceptible to breakage under external disturbances.

[0032] Tributyl phosphate reduces the surface viscosity of the liquid film, increasing the drainage rate of the liquid film. In summary, its effects include: 1. Inhibiting foaming: Tributyl phosphate forms a thin film on the liquid surface, blocking the formation and diffusion of bubbles, thus inhibiting foaming; 2. Rapid defoaming: Tributyl phosphate is a hydrophobic molecule; when it encounters bubbles, it quickly distributes on the bubble film, disrupting the foam film's equilibrium and achieving rapid defoaming; 3. Reducing viscosity: Tributyl phosphate can penetrate into the foam, interacting with liquid molecules and reducing the attraction between them, thereby lowering the liquid's viscosity; 4. Stability: Tributyl phosphate is insensitive to changes in temperature, pH, and other factors, exhibiting good stability and maintaining its defoaming effect in various industrial and production processes.

[0033] Defoaming active ingredients: The mechanism of action of defoaming ingredients in mineral oil-based defoamers is mainly through eliminating the elasticity of the foam surface, causing the foam to break down. Specifically, defoaming ingredients can be adsorbed onto the foam surface, reducing surface tension and disrupting the elasticity of the foam surface, thus causing the foam to break down. Defoaming ingredients in mineral oil-based defoamers are usually a mixture of multiple components, including surfactants, carriers, and additives. These components work synergistically to achieve the defoaming effect. Among them, surfactants are the core component of defoaming ingredients; they reduce the elasticity of the foam surface, making the foam easier to break down. Carriers and additives play a supporting role; they can increase the dispersibility and stability of the defoaming ingredients, allowing them to better exert their defoaming effect. In mineral oil-based defoamers, the mechanism of action of defoaming substances includes the following aspects: 1. Reducing surface tension: Defoaming substances can reduce the surface tension of the foam surface, destroying the elasticity of the foam surface and causing the foam to break; 2. Adsorption on the foam surface: Defoaming substances can be adsorbed on the foam surface, increasing the wettability of the foam surface and making the foam easier to break; 3. Disrupting the integrity of the foam film: Defoaming substances can penetrate into the foam interior, disrupting the integrity of the foam film, impairing the recovery and fluidity of the liquid film, thereby causing the foam to break; 4. Improving the fluidity of the foam: Defoaming substances can increase the fluidity inside the foam, making the foam easier to deform and break. The defoaming active substance of this invention is hydrophobic particles, hydrophobically modified titanium dioxide, compounded with ethylene bis-stearamide. The strong defoaming properties of the defoaming active substance formed by the compounding of hydrophobic modified titanium dioxide and ethylene bis-stearamide are mainly due to the following reasons: 1. Synergistic effect: The compounding of hydrophobic modified titanium dioxide and ethylene bis-stearamide may produce a synergistic effect, meaning that the combined effect of the two substances is greater than the sum of their individual effects. This synergistic effect can improve defoaming efficiency and better reduce foam stability; 2. Surface tension reduction: Ethylene bis-stearamide has the ability to reduce the surface tension of liquids, which helps to reduce the surface tension of foam and make the foam easier to break. Hydrophobic modified titanium dioxide provides high surface activity, increases the wettability and fluidity of the foam, and further promotes foam breakage; 3. Structural disruption: The hydrophobic properties of ethylene bis-stearamide allow it to insert into the liquid film of the foam, disrupting the foam structure. The near-nanoscale size of hydrophobic modified titanium dioxide allows it to penetrate the microstructure of foam, further disrupting its stability; 4. Anti-refoaming ability: Ethylene bis-stearamide can reduce the surface tension of the liquid, making the foam easier to break. At the same time, it can also prevent the liquid from immediately reforming into foam after breaking, improving the persistence of defoaming; 5. Wetting and penetration: Hydrophobic modified titanium dioxide has high surface activity and good wettability, which can quickly penetrate into the foam interior, thereby more effectively destroying the foam structure.In summary, the defoaming active substance formed by the combination of hydrophobic modified titanium dioxide and ethylene bis-stearamide has strong defoaming properties, mainly due to the combined effects of their synergistic effect, reduction of surface tension, disruption of foam structure, resistance to refoaming, and good wettability and permeability.

[0034] In summary, the mechanism of action of defoaming substances in mineral oil-based defoamers is mainly achieved by reducing surface tension, adsorbing onto the foam surface, disrupting the integrity of the foam film, and improving the flowability of the foam.

[0035] Defoaming aids: In mineral oil-based defoamers, defoaming aids primarily assist the defoamer in performing its defoaming function more effectively. They help the defoamer penetrate the foam more effectively, disrupting its stability and accelerating its collapse. Furthermore, defoaming aids can improve the dispersibility and stability of the defoamer, making it less prone to deterioration during transportation and storage. Specifically, defoaming aids can increase the wettability of the foam surface, allowing the defoamer to adhere better to the foam surface, thus accelerating foam collapse. They can also increase the internal flowability of the foam, making it easier to deform and break. In addition, defoaming aids can improve the penetration ability of the defoamer, enabling it to penetrate the foam more effectively and thus exert its defoaming effect more efficiently. It is important to note that the type and dosage of defoaming aids have a significant impact on the performance of mineral oil-based defoamers; therefore, in practical applications, it is necessary to select appropriate defoaming aids and optimize the formulation.

[0036] Fatty acid glycerides: Nonionic surfactants, fatty acid glycerides, can mitigate the impact of hydrophobic particles on the stability of mineral oil defoamers, primarily through the following mechanism of action:

[0037] 1. Reduces interfacial tension: Nonionic surfactants, such as fatty acid glycerides, reduce interfacial tension, decreasing the tension between hydrophobic particles and air, making it easier for these particles to be released from the mineral oil defoamer, thus improving the defoamer's stability. 2. Forms an interfacial film: Nonionic surfactants, such as fatty acid glycerides, can form a stable interfacial film at the interface between hydrophobic particles and air, preventing the aggregation and sedimentation of hydrophobic particles, thereby improving the stability of the mineral oil defoamer. 3. Improves dispersibility: Nonionic surfactants, such as fatty acid glycerides, improve the dispersibility of hydrophobic particles in mineral oil defoamers, allowing them to be more evenly distributed within the defoamer, thus reducing sedimentation and aggregation, and improving the defoamer's stability. 4. Increases viscosity: Nonionic surfactants, such as fatty acid glycerides, increase the viscosity of mineral oil defoamers, thereby reducing the movement and aggregation of hydrophobic particles and improving the defoamer's stability.

[0038] In summary, nonionic surfactants, such as fatty acid glycerides, can mitigate the impact of hydrophobic particles on the stability reduction of mineral oil defoamers, primarily through mechanisms such as reducing interfacial tension, forming an interfacial film, improving dispersibility, and increasing viscosity. These mechanisms effectively stabilize hydrophobic particles in mineral oil defoamers, thereby enhancing their defoaming effect.

[0039] Emulsifiers: Also known as defoamer additives, emulsifiers aim to enhance emulsification properties, thereby increasing the normal functioning of the defoamer, i.e., its stability. They typically account for about 10% of the composition of mineral oil-based defoamers. The main role of emulsifiers in mineral oil-based defoamers is to disperse the active ingredient (such as mineral oil) into small particles for better dispersion in oil or water, thus increasing the defoaming effect. Emulsifiers can also improve the stability of the defoamer, making it less prone to deterioration during transportation and storage.

[0040] Specifically, emulsifiers reduce surface tension, making it easier for active ingredients such as mineral oil to diffuse on the foam surface, thereby compromising foam stability. Furthermore, emulsifiers can also improve defoaming effects by forming emulsion microparticles, increasing the contact area between active ingredients like mineral oil and the foam surface.

[0041] It should be noted that the type and amount of emulsifier have a significant impact on the performance of mineral oil-based defoamers. Therefore, in practical applications, it is necessary to select appropriate emulsifiers and optimize the formulation.

[0042] Thickener Hydroxyethyl Cellulose: The mechanism of action of hydroxyethyl cellulose (HFC) in mineral oil defoamers is mainly achieved through its thickening, suspending, binding, emulsifying, and dispersing properties. 1. First, HFC increases the viscosity of the mineral oil defoamer, causing it to form a thick film on the foam surface, thereby inhibiting foam breakage. 2. Second, HFC, through its suspending properties, stably disperses hydrophobic particles in the mineral oil defoamer, preventing particle sedimentation and aggregation, thus improving the stability of the defoamer. 3. In addition, HFC also has emulsifying and dispersing properties, which can promote foam breakage and uniform liquid distribution, thereby better exerting its defoaming effect.

[0043] In summary, the mechanism of action of the thickener hydroxyethyl cellulose in mineral oil defoamers is mainly achieved by increasing viscosity, suspending hydrophobic particles, emulsifying and dispersing foam. These effects can effectively improve the stability and defoaming effect of the defoamer.

[0044] The beneficial effects of this invention are:

[0045] 1. The mineral oil-based defoamer of this invention has the advantages of low surface tension, good chemical stability, low dosage, fast defoaming speed, good compatibility with emulsions, and high temperature resistance;

[0046] 2. The mineral oil-based defoamer of this invention is not only inexpensive but also widely applicable. It can serve as a cheap alternative to expensive silicone defoamers and can be used in some situations where silicone defoamers are not suitable, such as in the production of laminating adhesives, where silicone defoamers can cause problems such as silicone spots and pinholes in the coating.

[0047] 3. The preparation method of the mineral oil-based defoamer of the present invention is simple and easy to operate, and has good acid and alkali resistance and high temperature resistance. At the same time, the raw materials are readily available and cost-effective. Detailed Implementation

[0048] To further understand the present invention, the following detailed description of a mineral oil-based defoamer and its preparation method provided by the present invention is provided in conjunction with embodiments.

[0049] In the following statements:

[0050] White oil: Model: 7#, CAS No.: 8042-47-5, Source: Wuhan Jixin Yibang Biotechnology Co., Ltd.

[0051] Microsilica powder: Model: SY-94 (semi-densified), average particle size 0.15 μm, specific surface area 20 m². 2 / g, source: Gansu Sanyuan Silicon Materials Co., Ltd.

[0052] The preparation method of hydrophobic modified titanium dioxide is described in reference to patent CN113044878B - A superhydrophobic modified titanium dioxide and its preparation method, Example 1.

[0053] Hydroxyethyl cellulose: Product number: 54290, brand: Sigma, viscosity 90-160 cP (5% in H2O, 25℃).

[0054] Example 1

[0055] The preparation method of the mineral oil-based defoamer in this embodiment is as follows:

[0056] S1. 8.0 g of tributyl phosphate, 6.6 g of hydrophobically modified titanium dioxide, 4.4 g of ethylene bis-stearamide, 8.0 g of defoaming agent isoamyl alcohol, and 9.0 g of glyceryl monopalmitate were added to 50.0 g of white oil and mixed and stirred for 25 min at a stirring speed of 350 rpm. Then, 8.0 g of thickener hydroxyethyl cellulose was added, and the mixture was stirred and heated to 90°C and kept at that temperature for 1.5 h. The mixture was then cooled to 40°C to obtain mixture A.

[0057] S2 mixes the above mixture A with 6.0 g of emulsifier Span 60 until uniform. After the mixture cools to room temperature, it is transferred to a grinding mill and ground and dispersed with 2.0 mm zircon beads for 2 h to obtain the mineral oil-based defoamer.

[0058] Example 2

[0059] The preparation method of the mineral oil-based defoamer in this embodiment is as follows:

[0060] S1. 8.0 g of tributyl phosphate, 6.6 g of hydrophobic modified titanium dioxide, 4.4 g of ethylene bis-stearamide, 8.0 g of defoaming agent isoamyl alcohol, and 9.0 g of glyceryl monopalmitate were added to 52.0 g of white oil and mixed and stirred for 25 min at a stirring speed of 350 rpm. Then, 8.0 g of thickener hydroxyethyl cellulose was added, and the mixture was stirred and heated to 90°C and kept at that temperature for 1.5 h. The mixture was then cooled to 40°C to obtain mixture A.

[0061] S2 mixes the above mixture A with 4.0 g of emulsifier Span 60 until uniform. After the mixture cools to room temperature, it is transferred to a grinding mill and ground and dispersed with 2.0 mm zircon beads for 2.0 h to obtain the mineral oil-based defoamer.

[0062] Example 3

[0063] The preparation method of the mineral oil-based defoamer in this embodiment is as follows:

[0064] S1. 8.0 g of tributyl phosphate, 6.6 g of hydrophobically modified titanium dioxide, 4.4 g of ethylene bis-stearamide, 10.0 g of defoaming agent isoamyl alcohol, and 9.0 g of glyceryl monopalmitate were added to 48.0 g of white oil and mixed and stirred for 25 min at a stirring speed of 350 rpm. Then, 10.0 g of thickener hydroxyethyl cellulose was added, and the mixture was stirred and heated to 90°C and kept at that temperature for 1.5 h. The mixture was then cooled to 40°C to obtain mixture A.

[0065] S2 mixes the above mixture A with 4.0 g of emulsifier Span 60 until uniform. After the mixture cools to room temperature, it is transferred to a grinding mill and ground and dispersed with 2.0 mm zircon beads for 2.0 h to obtain the mineral oil-based defoamer.

[0066] Example 4

[0067] The preparation method of the mineral oil-based defoamer in this embodiment is as follows:

[0068] S1. Add 8.0 g of tributyl phosphate, 11.0 g of hydrophobic silica, and 8.0 g of defoaming agent isoamyl alcohol to 59.0 g of white oil, mix and stir for 25 min at a stirring speed of 350 rpm, then add 8.0 g of thickener hydroxyethyl cellulose, continue stirring and heat to 90℃, keep at that temperature for 1.5 h, then cool to 40℃ to obtain mixture A;

[0069] S2 mixes the above mixture A with 6.0 g of emulsifier Span 60 until uniform. After the mixture cools to room temperature, it is transferred to a grinding mill and ground and dispersed with 2.0 mm zirconium beads for 2.0 h to obtain the mineral oil-based defoamer.

[0070] The preparation method of the hydrophobic silica is as follows:

[0071] S1 feeds 11.0 g of microsilica powder into a secondary magnetic separator to remove iron impurities, and then continues to perform high-temperature purification at 800℃ to remove volatile substances coated on its surface.

[0072] S2. The silica powder obtained in S1 is mixed with 1 g of hydrophobic agent dimethyl silicone oil, and stirred at room temperature and pressure for 30 min at a stirring speed of 600 rpm.

[0073] S3 The mixture obtained in S2 was placed in a constant temperature drying oven and activated at 220°C for 2 hours to remove hydrophobicity.

[0074] S4 involves ultra-fine grinding of the material obtained in S3 to obtain a particle size of 2000 mesh, thus yielding the hydrophobic silica.

[0075] Example 5

[0076] The preparation method of the mineral oil-based defoamer in this embodiment is as follows:

[0077] S1. Add 8.0 g of tributyl phosphate, 11.0 g of ethylene bis-stearamide, and 8.0 g of defoaming agent isoamyl alcohol to 59.0 g of white oil, mix and stir for 25 min at a stirring speed of 350 rpm, then add 8.0 g of thickener hydroxyethyl cellulose, continue stirring and heat to 90℃, keep at that temperature for 1.5 h, then cool to 40℃ to obtain mixture A;

[0078] S2 mixes the above mixture A with 6.0 g of emulsifier Span 60 until uniform. After the mixture cools to room temperature, it is transferred to a grinding mill and ground and dispersed with 2.0 mm zirconium beads for 2.0 h to obtain the mineral oil-based defoamer.

[0079] Example 6

[0080] The preparation method of the mineral oil-based defoamer in this embodiment is as follows:

[0081] S1. Add 8.0 g of tributyl phosphate, 11.0 g of hydrophobic modified titanium dioxide, and 8.0 g of defoaming agent isoamyl alcohol to 59.0 g of white oil, mix and stir for 25 min at a stirring speed of 350 rpm, then add 8.0 g of thickener hydroxyethyl cellulose, continue stirring and heat to 90℃, keep at that temperature for 1.5 h, then cool to 40℃ to obtain mixture A;

[0082] S2 mixes the above mixture A with 6.0 g of emulsifier Span 60 until uniform. After the mixture cools to room temperature, it is transferred to a grinding mill and ground and dispersed with 2.0 mm zirconium beads for 2.0 h to obtain the mineral oil-based defoamer.

[0083] Test Example 1: Performance tests of mineral oil-based defoamers prepared with different proportions of defoaming agents, emulsifiers, and thickeners.

[0084] The testing methods for the dispersion density, defoaming time, defoaming efficiency, dynamic stability, and compatibility with emulsion of the mineral oil-based defoamer described in Test Example 1 are the same as those for the following Test Examples. The reason for including Test Examples 1-3 in the Test Examples is to determine the optimal ratio of defoamer, emulsifier, and thickener.

[0085] Dispersion density: The specific test method is as follows: Add 200 g of emulsion (pure acrylic emulsion: styrene-acrylic emulsion = 1:1) and 0.3 g of defoamer to a 1000 mL plastic beaker, disperse at high speed of 1500 rpm for 15 min, and then immediately pour the emulsion from the beaker into a 500 mL graduated cylinder (the graduated cylinder is weighed beforehand and recorded as m), read the volume of the emulsion and record it as V, and weigh the total weight of the graduated cylinder and the emulsion and record it as M. The dispersion density of the emulsion (g / mL) = (Mm) / V. The higher the dispersion density, the better the defoaming effect of the defoamer.

[0086] The defoamer is the mineral oil-based defoamer prepared in each of the embodiments;

[0087] Defoaming time: The test method for defoaming time is the same as that for test example 3, and will not be repeated here;

[0088] Defoaming efficiency: The defoaming efficiency test method is the same as that in Test Example 4, and will not be repeated here;

[0089] Dynamic stability and emulsion compatibility: The dynamic stability test method and the emulsion compatibility test method are the same as those in Examples 6 and 7, respectively, and will not be repeated here.

[0090] Table 1. Performance tests of mineral oil-based defoamers prepared with different proportions of defoaming agents, emulsifiers, and thickeners.

[0091]

[0092] As shown in Table 1 above, the mineral oil-based defoamer prepared in Example 1 exhibits the best performance in all aspects. In Example 1, the mass ratio of the defoamer, emulsifier, and thickener was 4:3:4. Comparing Examples 1-3, it can be seen that changes in the mass ratio of the defoamer, emulsifier, and thickener affect the performance of the prepared defoamer. Possible reasons include: 1. The proportion of the defoamer: Defoamers typically enhance the defoaming effect. If the proportion of the defoamer is too high, it may reduce the stability of the defoamer, leading to a decrease in defoaming speed. Conversely, if the proportion of the defoamer is too low, it may not fully exert its defoaming effect, resulting in poor defoaming performance; 2. The proportion of the emulsifier: The main function of the emulsifier is to evenly disperse the defoamer in the foam system, thereby increasing the contact area between the defoamer and the foam. If the proportion of the emulsifier is too high, it may reduce the surface tension of the defoamer, leading to excessively fast defoaming speed. If the proportion of emulsifier is too low, its dispersing effect may not be fully realized, resulting in poor defoaming performance. 3. Thickener proportion: The main function of thickener is to increase the viscosity of the defoamer, thereby making it more stable in the foam system. If the proportion of thickener is too high, the defoamer may become too viscous, resulting in poor flowability and difficulty in dispersion. Conversely, if the proportion of thickener is too low, its stabilizing effect may not be fully realized, leading to problems such as sedimentation during storage and use.

[0093] In summary, Example 1, in which the mass ratio of defoamer, emulsifier, and thickener is 4:3:4, is the best example. Subsequent Examples 4-8 also use the same mass ratio of defoamer, emulsifier, and thickener of 4:3:4 for all subsequent tests.

[0094] Test Example 2: Dispersion density test of mineral oil-based defoamer and two commonly used defoamers

[0095] The defoaming performance of the mineral oil-based defoamers in Examples 1 and 4-8 was tested and compared with that of commercially available defoamers (Germany BYK-023 silicone defoamer and German Corning SN-DEFOAMER NXZ defoamer for water-based coatings).

[0096] The specific test method is as follows: Add 200 g of emulsion (pure acrylic emulsion: styrene-acrylic emulsion = 1:1) and 0.3 g of defoamer to a 1000 mL plastic cup. Disperse at a high speed of 1500 rpm for 15 min. Immediately afterward, pour the emulsion from the beaker into a 500 mL graduated cylinder (pre-weighed, recorded as m). Record the volume of the emulsion as V, and weigh the graduated cylinder and the emulsion together, recorded as M. The dispersion density of the emulsion (g / mL) = (Mm) / V. A higher dispersion density indicates a better defoaming effect of the defoamer. The test results are as follows:

[0097] Table 2. Dispersion density test results of the mineral oil-based defoamers prepared in Examples 1 and 4-6 and two commercially available defoamers.

[0098]

[0099] As can be seen from the test results in Table 2, the defoaming performance of the mineral oil-based defoamer prepared in Example 1 of the present invention is significantly better than that of the defoamers prepared in Examples 4-6 and the two commercially available defoamers. This indicates that the defoaming performance of the mineral oil-based defoamer of the present invention is excellent.

[0100] Comparing Example 1 and Example 4, it can be seen that the defoaming active material hydrophobically modified titanium dioxide in Example 1 interacts with ethylene bis-stearamide and is then combined with fatty acid glycerides. The resulting mineral oil-type defoamer has a higher dispersion density than that in Example 4, which does not include fatty acid glycerides. The possible reasons are: 1. Synergistic effect: There may be a synergistic effect between fatty acid glycerides, hydrophobically modified titanium dioxide, and ethylene bis-stearamide. 1. Fatty acid glycerides can improve the dispersibility of hydrophobically modified titanium dioxide and ethylene bis-stearamide in mineral oil, making them more evenly distributed in the mineral oil, thereby increasing the dispersion density of the defoamer; 2. Reduced interfacial tension: Fatty acid glycerides have the effect of reducing interfacial tension, which can reduce the tension between the mineral oil and air interface, making it easier for the defoamer to diffuse on the foam surface, thereby increasing its dispersion density; 3. Stable dispersion of hydrophobic particles: Fatty acid glycerides can improve the dispersibility of hydrophobic particles in mineral oil, making the hydrophobic particles more evenly distributed in the defoamer, thereby reducing their precipitation and aggregation, and improving the dispersion density of the defoamer; 4. Increased viscosity: Fatty acid glycerides can increase the viscosity of mineral oil defoamers, making them form a thicker film on the foam surface, thereby reducing foam breakage and improving the dispersion density of the defoamer.

[0101] In summary, the mineral oil-based defoamer obtained by combining hydrophobically modified titanium dioxide with ethylene bis-stearamide and then with fatty acid glycerides has a higher dispersion density than the defoamer without fatty acid glycerides. This is mainly due to the synergistic effect of the fatty acid glycerides, which reduces interfacial tension, stabilizes the dispersion of hydrophobic particles, and increases viscosity. These effects contribute to improving the stability and defoaming effect of the defoamer.

[0102] Comparing Examples 4-6, it can be seen that the dispersion density of the group with hydrophobic modified titanium dioxide as the defoaming active material is greater than that of the two groups with hydrophobic silica and ethylene bis-stearamide as the defoaming active materials. The possible reasons are: 1. Differences in physical properties: Hydrophobic modified titanium dioxide, ethylene bis-stearamide, and hydrophobic silica have different physical properties, such as particle size, shape, and surface energy. These factors may affect their dispersibility and stability in mineral oil, thus affecting the dispersion density; 2. Chemical compatibility: Hydrophobic modified titanium dioxide has good chemical compatibility with mineral oil and is less prone to chemical reactions or phase separation, thus maintaining a high dispersion density. Hydrophobic silica and ethylene bis-stearamide may exhibit certain chemical reactions or phase separation with mineral oil, resulting in lower dispersion densities; 3. Preparation process: The preparation process of the defoamer may affect its dispersion density. Different preparation methods may lead to differences in the particle size, shape, surface energy, and other physical properties of defoamers, thus affecting their dispersibility and stability in mineral oil; 4. Dosage: The amount of defoamer added may affect its dispersion density. When the dosage is high, the defoamer particles may form agglomerates in the mineral oil, resulting in a decrease in dispersion density. When the dosage is low, the defoamer particles may be more uniformly distributed in the mineral oil, thus maintaining a higher dispersion density.

[0103] In summary, the dispersion density of a group of mineral oil defoamers with hydrophobic modified titanium dioxide as the defoaming active ingredient is greater than that of two groups of defoamers with hydrophobic silica and ethylene bis-stearamide as the defoaming active ingredients. This is mainly due to differences in physical properties, chemical compatibility, preparation processes, and dosage. These factors contribute to improving the stability and defoaming effect of the defoamers.

[0104] Comparing Examples 1 and 4-6, it can be seen that the defoamer obtained by combining hydrophobic modified titanium dioxide with ethylene bis-stearamide has a higher dispersion density than either of the two uncombined defoamers. The possible reasons are: 1. Synergistic effect: Hydrophobic modified titanium dioxide and ethylene bis-stearamide may have a synergistic effect in the defoamer. They can work together to enhance the defoaming effect, resulting in better dispersion performance of the combined defoamer; 2. Reduced interfacial tension: Both hydrophobic modified titanium dioxide and ethylene bis-stearamide have the effect of reducing interfacial tension, which can reduce the tension between mineral oil and air, making the foam easier to break. After combination, their synergistic effect can further reduce interfacial tension and increase the dispersion density of the defoamer; 3. Stable dispersion of hydrophobic particles: Both hydrophobic modified titanium dioxide and ethylene bis-stearamide have hydrophobic properties, which can better adsorb onto the foam surface and disrupt the stability of the foam. After being compounded, they work together to distribute the hydrophobic particles more evenly in the defoamer, increasing its dispersion density; 4. Increased viscosity: Both hydrophobic modified titanium dioxide and ethylene bis-stearamide can increase the viscosity of mineral oil defoamers, thereby reducing foam movement and aggregation. After being compounded, their synergistic effect can further increase viscosity and improve the dispersion density of the defoamer.

[0105] In summary, the defoamer composed of hydrophobically modified titanium dioxide and ethylene bis-stearamide exhibits a higher dispersion density than either of the two uncombined defoamers. This is primarily due to synergistic effects, reduced interfacial tension, stable dispersion of hydrophobic particles, and increased viscosity. These effects contribute to improving the stability and defoaming effect of the defoamer.

[0106] Test Example 3: Defoaming performance (defoaming time) test of the mineral oil-based defoamers prepared in each example and two commercially available defoamers.

[0107] The defoaming performance of the mineral oil-based defoamers prepared in Examples 1 and 4-6 was tested and compared with that of commercially available defoamers (Germany BYK-023 silicone defoamer and German Corning SN-DEFOAMER NXZ defoamer for waterborne coatings).

[0108] Measure 50 mL of foaming solution into a 100 mL stoppered graduated cylinder. Use a pipette to add 1 mL of defoaming solution into the stoppered graduated cylinder. Adjust the solution temperature to the specified requirements, cover the cylinder, shake vigorously 30 times, and let it stand. Simultaneously, start a stopwatch and record the time required for the foam volume to decrease to less than 5 mL. The set temperature is 50℃.

[0109] Table 3. High-Temperature Defoaming Performance (Defoaming Time) Tests of Mineral Oil-Based Defoamers and Two Commercially Available Defoamers

[0110]

[0111] As shown in Table 3 above, Example 1, which is the mineral oil-based defoamer of the present invention, has the best defoaming performance.

[0112] Comparing Examples 1 and 4, it is evident that the defoamer of Example 1, with the addition of fatty acid glycerides, exhibits superior defoaming performance compared to Example 4, which does not contain fatty acid glycerides. The possible reasons for this are: 1. Improved stability of the defoamer: As a thickener, fatty acid glycerides increase the viscosity and stability of the defoamer, making it less prone to deterioration during transportation and storage. This helps maintain the defoaming performance of the defoamer, allowing it to perform better in practical applications; 2. Enhanced foam permeability: Fatty acid glycerides are hydrophilic, increasing the wettability of the defoamer on the foam surface, allowing it to penetrate the foam interior better. This helps to disrupt foam stability, accelerate foam breakage, and improve the defoaming efficiency of the defoamer; 3. Synergistic defoaming effect: There may be a synergistic effect between the hydrophobic modified titanium dioxide and ethylene bis-stearamide. They can work together to enhance the defoaming effect. When combined with fatty acid glycerides, this synergistic effect is further enhanced, thereby improving the overall defoaming performance of the defoamer; 4. Reducing interfacial tension: Fatty acid glycerides have the effect of reducing interfacial tension, which can reduce the tension at the interface between mineral oil and air, making the foam easier to break. After compounding, their synergistic effect can further reduce interfacial tension and improve the defoaming performance of the defoamer.

[0113] In summary, the mineral oil-based defoamer, obtained by combining hydrophobically modified titanium dioxide with ethylene bis-stearamide and then with fatty acid glycerides, exhibits superior defoaming performance compared to defoamers without fatty acid glycerides. This is primarily due to improved stability, enhanced foam permeability, synergistic defoaming effect, and reduced interfacial tension. These effects contribute to improving the practical application effectiveness of the defoamer.

[0114] Comparing Examples 4-6, it can be seen that the defoaming performance of the group of defoamers with hydrophobic modified titanium dioxide as the defoaming active material is better than that of the two groups of defoamers with hydrophobic silica and ethylene bis-stearamide as the defoaming active materials. The possible reasons are: 1. Differences in the chemical properties of the defoamers: The chemical properties of hydrophobic modified titanium dioxide differ from those of hydrophobic silica and ethylene bis-stearamide. Hydrophobic modified titanium dioxide has better solubility and dispersibility in mineral oil, and can more effectively adsorb onto the foam surface, thereby disrupting the foam's stability. Hydrophobic silica and ethylene bis-stearamide may have poorer solubility and dispersibility in mineral oil, resulting in poorer defoaming performance; 2. Particle size and shape of the defoamers: Different particle sizes and shapes of defoamer particles may affect defoaming performance. Generally, smaller particles have a larger specific surface area and can better adsorb onto the foam surface, thereby disrupting the foam's stability. Furthermore, particles of different shapes may have different defoaming mechanisms, which will also affect defoaming performance; 3. Foam properties: Different foam properties may affect the defoaming performance of defoamers. For example, the stability, surface tension, viscosity, and other properties of foam may affect the adsorption and destruction effect of defoamers on the foam surface.

[0115] In summary, the group of defoamers with hydrophobic modified titanium dioxide as the defoaming active material exhibits superior defoaming performance compared to the two groups with hydrophobic silica and ethylene bis-stearamide as the defoaming active materials. This is mainly due to differences in chemical properties, particle size and shape, and foam properties. These factors contribute to improving the practical application effect of defoamers.

[0116] Test Example 4: Defoaming and foam suppression efficiencies (%) of the mineral oil-based defoamers prepared in each example and two commercially available defoamers.

[0117] The defoaming performance of the mineral oil-based defoamers in Examples 1 and 4-6 was tested and compared with that of commercially available defoamers (Germany BYK-023 silicone defoamer and German Corning SN-DEFOAMER NXZ defoamer for water-based coatings).

[0118] The foam suppression test method is as follows: At room temperature, add 1 mL of soapy water, 20 mL of deionized water, and 1 mL of defoaming solution to a 100 mL stoppered graduated cylinder. Shake 30 times with the same force, then immediately start a stopwatch and record the foam volume after 300 seconds. A blank test is conducted without defoaming agent, under the same conditions. Calculate the foam suppression efficiency using the following formula:

[0119] r =[( V 1 - V 2 ) / V1 ]×100%

[0120] r —Foam suppression efficiency;

[0121] V 1 —Foam volume during blank test;

[0122] V 2 —The volume of foam after adding defoamer;

[0123] Defoaming test method: At room temperature, add 1 mL of soapy water and 20 mL of deionized water to a 100 mL stoppered graduated cylinder. Shake 30 times with the same force, then add 1 mL of defoaming solution. Simultaneously start a stopwatch and record the foam volume after 300 s. A blank test is conducted without defoaming agent, under the same conditions. Calculate the defoaming efficiency using the following formula:

[0124] r =[( V 1 - V 2 ) / V 1 ]×100%

[0125] r —Defoaming efficiency;

[0126] V 1 —Foam volume during blank test;

[0127] V 2 —The volume of foam after adding defoamer;

[0128] Table 4. Foam suppression and defoaming efficiency test results of the mineral oil-based defoamers prepared in each example and two commercially available defoamers.

[0129]

[0130] As can be seen from Table 4 (Examples 1 and 4-6), the mineral oil-based defoamers prepared in Examples 1 and 6 exhibit better foam suppression and defoaming effects. The possible reasons are: 1. Synergistic foam suppression effect: Hydrophobic modified titanium dioxide and ethylene bis-stearamide have a synergistic effect in both foam suppression and defoaming. When combined, they can simultaneously inhibit foam generation and breakage, thus more comprehensively exerting their foam suppression and defoaming properties. In contrast, using either substance alone may result in relatively weaker foam suppression and defoaming effects; 2. Reduction of interfacial tension: Both hydrophobic modified titanium dioxide and ethylene bis-stearamide have the effect of reducing interfacial tension, which can reduce the strength of the foam liquid film and make the foam easier to break. After compounding, their synergistic effect can further reduce interfacial tension and improve foam suppression and defoaming performance; 3. Stable dispersion of hydrophobic particles: Both hydrophobic modified titanium dioxide and ethylene bis-stearamide have hydrophobic properties, which can better adsorb onto the foam surface and disrupt the stability of the foam. After compounding, they can work together to distribute hydrophobic particles more evenly in the defoamer, improving its foam suppression and defoaming performance; 4. Enhanced interaction: Hydrophobic modified titanium dioxide and ethylene bis-stearamide may interact after compounding, such as through hydrogen bonds and ionic bonds. These interactions can enhance the performance of the defoamer. Through interaction, the two substances can work together better to achieve better foam suppression and defoaming effects; 5. Extended foam contact time: Both hydrophobic modified titanium dioxide and ethylene bis-stearamide have a longer foam contact time, allowing the defoamer more opportunities to contact the foam, thus more effectively inhibiting foam generation and breakage. After compounding, their synergistic effect can further extend the foam contact time and improve foam suppression and defoaming performance.

[0131] In summary, the defoamer composed of hydrophobically modified titanium dioxide and ethylene bis-stearamide exhibits superior defoaming and foam-suppressing performance compared to either of the two uncombined defoamers. This superiority is primarily due to synergistic foam-suppressing effects, reduced interfacial tension, stable dispersion of hydrophobic particles, enhanced interactions, and prolonged foam contact time. These effects contribute to improving the effectiveness of the defoamer in practical applications.

[0132] Comparing Examples 4-6, it is evident that the group of defoamers with hydrophobic modified titanium dioxide as the defoaming active ingredient exhibits superior defoaming and foam-suppressing performance compared to the two groups of defoamers with hydrophobic silica and ethylene bis-stearamide as the defoaming active ingredients. The possible reasons for this are: 1. Chemical properties and surface activity: The chemical properties and surface activity of hydrophobic modified titanium dioxide give it better solubility and dispersibility in mineral oil, allowing it to more effectively adsorb onto the foam surface and thus disrupt foam stability. In contrast, hydrophobic silica and ethylene bis-stearamide may have poorer solubility and dispersibility in mineral oil, resulting in poorer defoaming and foam-suppressing performance; 2. Particle shape and size: Different particle shapes and sizes may affect the defoaming and foam-suppressing performance of defoamers. The particle shape and size of hydrophobic modified titanium dioxide may give it better adsorption and stability on the foam surface, thus more effectively disrupting the foam. The particle shape and size of hydrophobic silica and ethylene bis-stearamide may not be well-suited for adsorption on foam surfaces, resulting in poor defoaming and foam-suppressing performance. 4. Wide applicability: Hydrophobic modified titanium dioxide is suitable for various types of mineral oils, exhibiting a wide range of applications. Hydrophobic silica and ethylene bis-stearamide, on the other hand, may only be suitable for certain specific types of mineral oils, with a relatively narrow application range. Therefore, among various types of mineral oils, hydrophobic modified titanium dioxide has better defoaming and foam-suppressing performance. 5. Stability and heat resistance: Hydrophobic modified titanium dioxide exhibits good stability and heat resistance, maintaining effective defoaming and foam-suppressing performance under high-temperature conditions. In contrast, the combination of hydrophobic silica and ethylene bis-stearamide may have stability or heat resistance issues, leading to a decrease in its defoaming and foam-suppressing performance under high-temperature conditions.

[0133] In summary, the defoaming and foam-suppressing performance of the defoamer with hydrophobic modified titanium dioxide as the active ingredient is superior to that of the two groups of defoamers with hydrophobic silica and ethylene bis-stearamide as the active ingredients. This is mainly due to the influence of factors such as chemical properties and surface activity, particle shape and size, synergistic effect, wide applicability, stability, and heat resistance. These factors contribute to improving the effectiveness of defoamers in practical applications.

[0134] Comparing Examples 1 and 4, it can be seen that the defoaming and foam-suppressing performance of the mineral oil-based defoamer in Example 1 is superior to that in Example 4. The possible reasons are: 1. Synergistic effect: There may be a synergistic effect between fatty acid glycerides and other components in the mineral oil defoamer. Fatty acid glycerides can increase the adsorption and penetration of the defoamer on the foam surface, disrupting foam stability. They can also interact with other components of the mineral oil defoamer to jointly enhance the foam-suppressing and defoaming effects; 2. Reduced interfacial tension: Fatty acid glycerides have the effect of reducing interfacial tension, which can reduce the strength of the foam film, making the foam easier to break. When fatty acid glycerides are added to the mineral oil defoamer, their effect of reducing interfacial tension is enhanced, thereby improving the foam-suppressing and defoaming performance; 3. Improved dispersibility and stability: Fatty acid glycerides have good solubility and dispersibility in mineral oil, which can increase the stability and dispersibility of the defoamer, reducing the occurrence of sedimentation and stratification. This improvement helps maintain the foam-suppressing and defoaming properties of the defoamer; 4. Extending foam contact time: Fatty acid glycerides can increase the adsorption and adhesion of the defoamer on the foam surface, giving the defoamer more opportunities to contact the foam, thereby extending the foam contact time. By extending the foam contact time, the defoamer has more opportunities to break down the foam, improving its foam-suppressing and defoaming performance; 5. Enhancing heat resistance: Fatty acid glycerides have a certain degree of heat resistance, which can improve the heat resistance of mineral oil defoamers to some extent. Under high-temperature conditions, this heat resistance helps maintain the foam-suppressing and defoaming performance of the defoamer.

[0135] In summary, the addition of fatty acid glycerides to mineral oil defoamers improves their foam-suppressing and defoaming properties, mainly due to synergistic effects, reduced interfacial tension, improved dispersibility and stability, extended foam contact time, and enhanced heat resistance. These factors contribute to improving the effectiveness of defoamers in practical applications.

[0136] Test Example 5: Dynamic stability test of the mineral oil-based defoamer prepared in Examples 1, 4-6 and two commercially available defoamers.

[0137] The defoaming performance of the mineral oil-based defoamers in Examples 1 and 4-6 was tested and compared with that of commercially available defoamers (Germany BYK-023 silicone defoamer and German Corning SN-DEFOAMER NXZ defoamer for water-based coatings).

[0138] Dynamic stability tests were conducted in accordance with the standard GB / T 26527-2011 Organosilicon Defoamers.

[0139] Stability test: Instruments: Low-speed electric centrifuge: fixed-angle rotor, maximum speed not exceeding 5000 rpm, such as type 80-2; graduated centrifuge tubes: 10 mL;

[0140] Analytical Procedure: 8 mL of the mineral oil-based defoamer prepared in Examples 1 and 4-6 were measured using two 10 mL graduated centrifuge tubes. The samples were symmetrically placed in a centrifuge and continuously rotated at 3000 rpm for 15 min. The tubes were then removed, and the volume of the separated liquid was recorded. The arithmetic mean of the two measurements was taken as the result. The results are shown in Table 5 below.

[0141] Table 5. Dynamic stability tests of the mineral oil-based defoamers prepared in Examples 1 and 4-6 and two commercially available defoamers.

[0142]

[0143] As shown in Table 5 above, the mineral oil-based defoamer prepared in Example 1, which is the preferred embodiment of the present invention, exhibits the best dynamic stability, with no oil precipitation or sedimentation. Compared to Example 1, Example 4 shows a small amount of sedimentation. The difference lies in the fact that Example 1 uses a combination of the defoaming active ingredient and fatty acid glycerides, while Example 4 does not. The difference in dynamic stability between Examples 1 and 4 may be due to the following reasons: 1. The nonionic surfactant fatty acid glycerides help improve the stability of the defoamer. It may reduce the tendency for sedimentation and oil precipitation by lowering interfacial tension, increasing dispersibility, and reducing the likelihood of precipitation. Without this surfactant, the stability of the system may decrease, leading to a very small amount of sedimentation; 2. Furthermore, there may be interactions between the components of the defoamer. For example, hydrophobically modified titanium dioxide and ethylene bis-stearamide may produce sedimentation through some chemical or physical action. Adding fatty acid glycerides may alter this interaction and improve the stability of the system. However, the formation of sedimentation may also be related to external factors such as temperature, storage time, and stirring conditions. Therefore, further experiments and investigations may be needed to more accurately determine the cause.

[0144] Comparing Examples 1 and 4-6, it is evident that the mineral oil-based defoamer prepared by compounding the defoaming active material hydrophobically modified titanium dioxide with ethylene bis-stearamide, and then further compounding it with fatty acid glycerides, exhibits the best dynamic stability. The possible reasons are: 1. Synergistic effect: Both hydrophobically modified titanium dioxide and ethylene bis-stearamide possess defoaming activity, but they may function through different mechanisms. Combining them may produce a synergistic effect, meaning the combined effect of the two components is greater than the sum of their individual effects. This synergistic effect may enhance the dynamic stability of the defoamer; 2. Reduced interfacial tension: Fatty acid glycerides are surfactants that can reduce interfacial tension. This helps reduce foam stability and makes it easier for the defoamer to penetrate the foam, thereby accelerating the foam's collapse rate. Low interfacial tension contributes to improved dynamic stability of the defoamer; 3. Increased dispersibility: Fatty acid glycerides may increase the dispersibility of the defoamer in mineral oil. When defoamers are more evenly dispersed in mineral oil, they can more effectively contact and break down foam, thus improving the dynamic stability of the defoamer; 4. Anti-precipitation and oil separation: As a nonionic surfactant, fatty acid glycerides can reduce the tendency for precipitation and oil separation by lowering interfacial tension and increasing dispersibility. This helps maintain the stability of the defoamer, allowing it to maintain better performance during storage and use; 5. Effects of temperature and time: The dynamic stability of defoamers can also be affected by temperature and time. At appropriate temperatures, fatty acid glycerides may help slow down the oxidation process of defoamers, thereby extending their service life. In addition, over time, the active ingredients of defoamers may be gradually released, leading to a decrease in dynamic stability. However, this trend can be mitigated by formulation with fatty acid glycerides.

[0145] In summary, mineral oil-based defoamers prepared by combining hydrophobically modified titanium dioxide, ethylene bis-stearamide, and fatty acid glycerides may collectively enhance their dynamic stability through multiple mechanisms. However, further experiments and research are needed to confirm these hypotheses.

[0146] Comparing Examples 4-6, it can be seen that the mineral oil-based defoamer prepared in Example 6 exhibits better dynamic stability than that in Examples 4 and 5. The possible reasons are: 1. Chemical properties and mechanisms of action: The chemical properties and mechanisms of action of hydrophobic modified titanium dioxide may differ from those of hydrophobic silica and ethylene bis-stearamide. Hydrophobic modified titanium dioxide may more effectively disrupt the stable structure of foam, thus exhibiting better defoaming performance under dynamic conditions; 2. Surface tension: Different defoaming active substances may have different effects on surface tension. Hydrophobic modified titanium dioxide reduces the surface tension of foam, making it easier for the foam to break. In contrast, hydrophobic silica and ethylene bis-stearamide may have a smaller effect on surface tension, thus affecting their dynamic stability; 3. Compatibility: Different defoaming active substances may have different compatibility with mineral oil. Hydrophobic modified titanium dioxide may be more compatible with mineral oil, thus functioning more effectively under dynamic conditions. Hydrophobic silica and ethylene bis-stearamide may have poor compatibility with mineral oil, affecting their dynamic stability; 4. Particle size and dispersibility: The particle size and dispersibility of different defoaming actives may affect their dispersion and distribution in mineral oil. Smaller particle size and better dispersibility help improve the dynamic stability of defoamers. Therefore, the particle size and dispersibility of hydrophobic modified titanium dioxide may be more conducive to improving dynamic stability; 5. Effects of temperature and time: The dynamic stability of defoamers may also be affected by temperature and time. Under certain conditions, hydrophobic silica and ethylene bis-stearamide may undergo physical or chemical changes with the passage of temperature and time, leading to a decrease in dynamic stability. Hydrophobic modified titanium dioxide may have better tolerance and stability, thus maintaining better dynamic performance.

[0147] It should be noted that these are only some speculations about possible causes. To draw more definitive conclusions, more experiments and research are needed to gain a deeper understanding of the mechanisms by which different defoaming active ingredients affect the dynamic stability of defoamers.

[0148] Test Example 6: Thermal stability test of mineral oil-based defoamer and two commercially available defoamers

[0149] The defoaming performance of the mineral oil-based defoamers in Examples 1 and 4-6 was tested and compared with that of commercially available defoamers (Germany BYK-023 silicone defoamer and German Corning SN-DEFOAMER NXZ defoamer for water-based coatings).

[0150] Take equal masses of Examples 1, Examples 4-6 and two commercially available defoamers, add 50 g of black liquor, raise the temperature to 80°C, let stand for 24 h, and observe whether there is oil floating phenomenon. The performance test results are shown in Table 6 below.

[0151] The black liquor mentioned above refers to the washing liquor of pulp after washing and cooking during the persulfate or caustic soda pulp production process.

[0152] Table 6 Thermal stability test of mineral oil-based defoamers and two common commercial defoamers

[0153]

[0154] As can be seen from Examples 1 and 4-6 above, Example 1, namely the mineral oil-based defoamer of this invention, exhibits the best thermal stability. The possible reasons are: 1. Chemical stability: Hydrophobic modified titanium dioxide may have good chemical stability at high temperatures. This means that at higher temperatures, they are less prone to decomposition or deterioration, thus maintaining their defoaming activity. This stability may be related to their reactivity and chemical structure at high temperatures; 2. Thickening effect of fatty acid glycerides: As a surfactant, fatty acid glycerides may have a thickening effect. They can form a gel-like structure in the defoamer, increasing the viscosity of the system. This thickening effect may help improve the thermal stability of the defoamer because it can reduce the fluidity of the defoamer at high temperatures, making it more difficult to decompose or deteriorate; 3. Interactions and synergistic effects: There may be interactions and synergistic effects between hydrophobic modified titanium dioxide, ethylene bis-stearamide, and fatty acid glycerides. These components may combine to form a more stable complex or structure. This interaction may enhance the binding force between them, thereby improving the thermal stability of the system; 4. Coefficient of thermal expansion and compatibility: The coefficients of thermal expansion and compatibility of different components may affect the thermal stability of the system. If these components have similar coefficients of thermal expansion and good compatibility, they may have better stability when the temperature changes. This helps to reduce precipitation, separation, or deterioration caused by temperature changes; 5. Antioxidant capacity: High temperatures may cause oxidation or decomposition of some components. However, fatty acid glycerides may have better antioxidant capacity, which can slow down the oxidation process of other components. This helps to maintain the stability of the defoamer, allowing it to maintain its activity for a longer period of time at high temperatures.

[0155] In summary, mineral oil-based defoamers prepared by combining hydrophobically modified titanium dioxide and fatty acid glycerides may collectively enhance their thermal stability through multiple mechanisms. However, further experiments and research are needed to confirm these hypotheses.

[0156] Test Example 7: Compatibility Test of Mineral Oil-Based Defoamer with Two Commercially Available Defoamers

[0157] According to the standard GB / T 21089.1-2007 Test methods for application performance of water-based additives in architectural coatings - Part 1: Dispersants, defoamers and thickeners

[0158] The defoaming performance of the mineral oil-based defoamers in Examples 1 and 4-6 was tested and compared with that of commercially available defoamers (Germany BYK-023 silicone defoamer and German Corning SN-DEFOAMER NXZ defoamer for water-based coatings).

[0159] The uniformity of the defoamer after mixing with the emulsion.

[0160] Raw material: Styrene-acrylic emulsion

[0161] Instruments: Wet film preparation apparatus: 75 μm; Stainless steel cup: 250 mL; Glass plate: colorless and transparent, 150 mm × 120 mm × 3 mm or 3M company projection slide plastic film; Magnifying glass: 10x.

[0162] Operating steps: 1) Take 20 g of the emulsion-defoamer mixture system prepared according to 5.5.4.2, stirred at 500 r / min for 90 s, and let it stand for 24 h; 2) Prepare a coating on a clean glass plate or slide plastic film using a 75 μm wet film preparation apparatus. After it is surface dry, turn the test plate away from the light source and observe it with normal vision or corrected normal vision. The observation area is a rectangle of 50 mm × 40 mm (70 mm is deducted inward from the beginning of the coating, 30 mm is deducted inward from the end of the coating, and 40 mm is deducted from each side of the coating).

[0163] Result evaluation: Assess the number of pinholes in the coating according to Table 8, and assess the pinhole size according to Table 9. For example: A2-S3 indicates that the number of pinholes in the coating is grade 2, and the pinhole size is grade 3, which includes a small number of pinholes with a diameter of less than 0.5 mm.

[0164] Table 7. Compatibility test of the mineral oil-based defoamer with two commercially available defoamers in this embodiment.

[0165]

[0166] Table 8. Number Grades of Shrinkage Cavities

[0167]

[0168] Table 9. Cavity Size Grades

[0169]

[0170] As can be seen from Table 7 above, the mineral oil-based defoamer of this invention and Example 1 exhibit excellent compatibility. The possible reasons are: 1. Solubilizing effect of surfactants: Fatty acid glycerides, as nonionic surfactants, can increase the solubility of other components in the emulsion. They may form micelles or microemulsions in the emulsion, thus providing a more uniform dispersion environment. This solubilizing effect helps improve the compatibility between the defoamer and the emulsion; 2. Reduced interfacial tension: Fatty acid glycerides, as special nonionic surfactants, can reduce interfacial tension, making it easier for the defoamer to penetrate into the emulsion. Reduced interfacial tension helps reduce foam stability, allowing the defoamer to more effectively break down the foam. This increased penetration may further improve the compatibility between the defoamer and the emulsion; 3. Structural similarity: The hydrophobic modified titanium dioxide and ethylene bis-stearamide may have some structural similarity to the components of the emulsion, which helps improve their compatibility. Structural similarity may make these components more likely to interact with other components in the emulsion, thus forming a more homogeneous system; 4. Interactions and synergistic effects: There may be interactions and synergistic effects between hydrophobically modified titanium dioxide, ethylene bis-stearamide, and fatty acid glycerides, which may enhance their compatibility with the emulsion. These components may combine with each other to form a more stable complex or structure, thereby improving their dispersibility and stability in the emulsion; 5. Particle size and dispersibility: The particle size and dispersibility of defoamers may affect their compatibility with the emulsion. Smaller particle size and good dispersibility help improve the compatibility of defoamers with the emulsion. Therefore, the particle size and dispersibility of hydrophobically modified titanium dioxide, ethylene bis-stearamide, and fatty acid glycerides may help improve their compatibility with the emulsion.

[0171] In summary, mineral oil-based defoamers prepared by combining hydrophobically modified titanium dioxide, ethylene bis-stearamide, and fatty acid glycerides may collectively improve their compatibility with emulsions through multiple mechanisms. However, further experiments and research are needed to confirm these hypotheses.

[0172] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, substitutions, or improvements made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing a mineral oil type antifoaming agent, characterized by, The following components are included by weight parts: Step 1: 5-10 parts of tributyl phosphate, 10-15 parts of defoaming active substance, 5-10 parts of defoaming auxiliary, 5-10 parts of fatty acid glyceride are added into 40-60 parts of mineral oil respectively, mixed and stirred for 20-30 min, the stirring speed is 300-400 rpm, 5-10 parts of thickening agent is continuously added, the temperature is continuously stirred to 70-100℃, and the temperature is kept for 1-2 h, the temperature is cooled to 30-50℃, and mixture A is obtained; Step 2: the mixture A is mixed with 1-10 parts of emulsifier uniformly, the mixed product is cooled to room temperature, and is transferred into a sand mill to be ground and dispersed with 1-2 mm zirconium beads for 1-2 h, and the mineral oil type defoaming agent is obtained. The defoaming active substance is a mixture of hydrophobic modified titanium dioxide and ethylene bis-stearamide in a mass ratio of (1-3) :

1.

2. The method for preparing a mineral oil-based defoamer according to claim 1, characterized in that: The defoaming active substance is a mixture of hydrophobic modified titanium dioxide and ethylene bis-stearamide in a mass ratio of 1.5:

1.

3. The method for preparing a mineral oil-based defoamer according to claim 1, characterized in that: The mineral oil is at least one of white oil, peppermint oil, corn oil, liquid paraffin, and alkylbenzene.

4. The method for preparing a mineral oil-based defoamer according to claim 1, characterized in that: The titanium dioxide is rutile type.

5. The method for preparing a mineral oil-based defoamer according to claim 1, characterized in that: The defoaming auxiliary is at least one of diethyl ether, isoamyl alcohol, polyether, triethanolamine, n-octanol, and iso-octanol.

6. The method for preparing a mineral oil-based defoamer according to claim 1, characterized in that: The fatty acid glyceride is at least one of glycerol monostearate, glycerol monopalmitate, glycerol monolaurate, and glycerol monooleate.

7. The method for preparing a mineral oil-based defoamer according to claim 1, characterized in that: The emulsifier is at least one of Span 20, Span 60, and Span 80.

8. The method for preparing a mineral oil-based defoamer according to claim 1, characterized in that: The thickening agent is at least one of hydroxyethyl cellulose, polyvinyl alcohol, and sodium alginate.

9. A mineral oil type antifoam agent characterized by: Prepared by the method of any one of claims 1-8.

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