Synthesis and production process of novel siloxane foam inhibitor

Abstract

The invention discloses a synthesis and production process of a novel siloxane foam inhibitor. The foam inhibitor comprises the following components in parts by weight: 2-10 parts of hydrophobic treated fumed silica or nano silicon dioxide filler, 40-70 parts of a silicone oil concentrated composition, 40-70 parts of high-viscosity polydimethylsiloxane and 100-150 parts of a fatty alcohol and epoxypropane polymer. There are two types of silicone oil concentrated compositions, the structures and chain lengths of the silicone oil concentrated compositions are various, 16 types are provided, and the preparation method is clear. The filler is subjected to special hydrophobization treatment, and the preparation process comprises the steps of mixing with a silicone oil concentrate, reacting and heating, and centrifugally separating. The production process comprises the following steps: mixing the components according to a specific ratio, stirring at a high speed, adding oleic acid, and heating to react to obtain the novel siloxane foam inhibitor. All the components have a synergistic effect, the foam inhibiting and defoaming capacity is improved, the process steps are simple, operation and control are easy, the product universality is high, the performance is excellent in a high-viscosity oily system, the foam problem of multiple oily systems is effectively solved, the cost is low, the efficiency is high, the performance is adjustable, and good stability and compatibility are achieved.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and specifically designs a synthesis and production process of a novel silicone antifoaming agent. The antifoaming agent is specifically used to prevent foaming of oily media, especially high-viscosity oily systems. Background Art

[0002] Organic silicon composite defoamers have extremely low interfacial tension, can effectively inhibit the formation of bubbles, remain stable at high temperatures, can be used in various chemical environments, and are non-toxic and stable. In recent years, people have been studying how to optimize the structure of organic silicon compounds to improve their performance. Polydimethylsiloxane is a linear structure without hydrogen atoms. It has low interfacial tension and excellent defoaming performance. In this case, hydrogen-containing polydimethylsiloxane substituted with hydrogen at the end or repeating unit can be used to enhance the defoaming effect. The methyl group combined with hydrogen reduces the interfacial tension through hydrogen bonds and van der Waals forces, which reduces the stability of the foam and accelerates the defoaming. Therefore, it can reduce the size of bubbles, inhibit the formation of bubbles, and help the defoamer to work effectively. But it affects the viscosity and fluidity of the siloxane compound, making it less stable, so a proper balance must be maintained. In addition to the hydrogen content, the length of the siloxane chain is also one of the factors that has a great influence on the defoaming ability. Siloxanes with shorter chain lengths have higher interfacial activity, thus having better defoaming characteristics, but have limited ability to stabilize and inhibit foam, so they are less sustainable. Longer chain lengths provide higher viscosity and more stable suppression of foam generation, but the foam breaking performance decreases, and the thermal and chemical stability also becomes higher.

[0003] It is well known that highly effective defoamers, so-called defoamer compounds, can be prepared from non-polar oils and fine solid particles as fillers, but existing production methods are complex and uneconomical, and there are problems with dispersibility and compatibility. According to patents US3235509A and US3560401A, the non-polar oil is usually polydimethylsiloxane, and the filler is silica that has been heated to 100 to 300°C for several hours under the catalysis of an alkali catalyst such as an alkali silicate or alkali hydroxide to make it hydrophobic. The use of partially rubberized cross-linked polydimethylsiloxane in patent US2632736A to promote the effect of defoamers has long been known, and in addition, such products can also be prepared by free radical cross-linking of polydimethylsiloxane.

[0004] In order to produce a composite silicone defoamer with high defoaming ability, it is necessary to synthesize an organosiloxane and use it in a concentrated oil composition, but this is a multi-step process that is complicated and uneconomical. In addition, when polydimethylsiloxane is used as a concentrated oil composition, a single polysiloxane oil may cause dispersibility and water-in-oil compatibility problems. Summary of the invention

[0005] The purpose of the present invention is to provide a novel synthesis and production process of a silicone antifoam agent, specifically a silicone foam inhibitor containing hydrogen atoms, a preparation process thereof and a silicone composite antifoam agent composition. More specifically, the present invention relates to an antifoam agent based on silicone oil and a filler with a special characteristic of hydrophobicity, which is particularly suitable for limiting foam generation or inhibiting foam rather than reducing foam, and is used in preventing foaming of oily media, especially high-viscosity oily systems.

[0006] The synthesis and production process of the novel silicone foam suppressor of the present invention includes the preparation process of the silicone foam suppressor, the formula design of the silicone composite foam suppressor composition and the application technology thereof in the oily system. In terms of chemical synthesis, it involves the treatment and reaction of raw materials such as methyl cyclosiloxane, cyclosiloxane containing hydrogen atoms, linear siloxane, and the application technology of catalysts, fillers, fumed white carbon black or nano-silicon dioxide.

[0007] According to the production process of the novel silicone foam suppressor provided by the present invention, a low-hydrogen silicone oil with a certain molecular weight and a specific structure is prepared, which has a lower surface tension than the general polydimethylsiloxane surface tension, and has the characteristics of low surface tension and easy dispersion of the polymer of non-ionic surfactant fatty alcohol and propylene oxide, and can be blended with high-viscosity polysiloxane to improve the ability and stability of defoaming and degassing, as well as the stability and compatibility, dispersibility and high temperature resistance, resistance to hydroxyl and inorganic salts in oil and oily fluids, and can be used for foam suppression under difficult conditions. The filler after hydrophobic treatment can reduce the attraction between particles to achieve good dispersion and avoid agglomeration, thereby more effectively suppressing foam; in an oily system, its surface properties are more matched with the oily environment, which can enhance compatibility, reduce adverse effects, and improve stability and applicability; it can also cooperate with other ingredients to improve defoaming and foam suppression performance, and help enhance initial defoaming and foam breaking properties.

[0008] The present invention provides a novel silicone foam suppressor formulation, comprising a filler, a silicone oil concentrated composition, a high-viscosity polydimethylsiloxane, and a fatty alcohol and propylene oxide polymer in a specific ratio, wherein the components act synergistically to achieve a better foam suppression effect. The novel silicone foam suppressor compounding method provided by the present invention improves the stability of the foam suppressor, such as high temperature stability, storage stability, no shrinkage cavities, phase change, and coloring, and can be used in all oily foaming liquid systems, especially high-viscosity oily systems.

[0009] The invention provides a novel silicone foam suppressor, comprising: 2-10 parts of filler, 40-70 parts of silicone oil concentrated composition, 40-70 parts of high-viscosity polydimethylsiloxane and 100-150 parts of fatty alcohol and propylene oxide polymer; the filler is a hydrophobic treated filler.

[0010] The formula combination of the present invention adopts the composition of specific proportion and type, and the silicone oil concentrated composition, high viscosity polydimethylsiloxane and fatty alcohol are matched with propylene oxide polymer in a specific proportion, which can effectively suppress the generation of bubbles and stabilize foam in the oily system, and realize the foam suppression effect by changing the surface tension and interfacial properties of the system. The hydrophobic filler can be better dispersed in the foam suppressor system at a ratio of 2-10 parts, avoid agglomeration, and ensure that it is evenly distributed in the whole system, so as to give full play to its foam suppression effect. In oily media, especially high viscosity oily systems, hydrophobic treatment makes the filler more compatible with the system environment, reduces the problems such as precipitation and stratification caused by incompatibility, improves the stability and applicability of the foam suppressor in the oily system, and then enhances the overall foam suppression effect. The filler can also work in synergy with other ingredients to destroy the stability of bubbles, accelerate bubble rupture, and further improve the defoaming and foam suppression performance of the foam suppressor, especially in the early stage of foam generation, can quickly play a role, and enhance the initial defoaming and foam breaking properties.

[0011] Silicone oil concentrate composition is a key component of antifoaming agent. As the core antifoaming component, the silicone oil concentrate composition works synergistically with other components such as high-viscosity polydimethylsiloxane, fatty alcohol and propylene oxide polymer, and filler to jointly inhibit the generation of bubbles in the oily system. By adjusting its own structure and component ratio, the surface tension and interfacial properties of the system can be effectively changed, thereby achieving a good antifoaming effect. At the same time, by adjusting the chain length and ratio of its structural parameters, an oily concentrated antifoaming agent composition with different structures and chain lengths can be prepared. The optimizability of this structure can accurately improve the antifoaming ability and storage stability for different oily systems and application requirements. In addition, its own stability and good compatibility with other components are crucial to ensuring the quality and stability of the antifoaming agent product. During storage, the appropriate silicone oil concentrate composition structure can prevent the occurrence of adverse phenomena such as phase separation, ensuring that the antifoaming agent can still maintain good performance after long-term storage.

[0012] Preferably, the silicone oil concentrated composition comprises two silicone oil concentrated compositions, and the structure thereof is Formula 1:

[0013]

[0014] Formula 2:

[0015] ,

[0016] In the construction formula:

[0017] R1 is a methyl group, R2 is a hydrogen atom, m is 0 to 50, n is 1 to 150, and the structure includes a variety of different chain lengths;

[0018] Specifically, when n is 2 to 5 times of m, preferably 2.8 to 4 times of m, including:

[0019] 0≤m≤25 (Formula 1-1), (Formula 2-1);

[0020] 26≤m≤55 (Formula 1-2), (Formula 2-2);

[0021] 56≤m≤85 (Formula 1-3), (Formula 2-3);

[0022] 86≤m≤125 (Formula 1-4), (Formula 2-4);

[0023] When n is 20 to 50 times, preferably 28 to 40 times, m, including:

[0024] 0≤m≤25 (Formula 1-5), (Formula 2-5);

[0025] 26≤m≤55 (Formula 1-6), (Formula 2-6);

[0026] 56≤m≤85 (Formula 1-7), (Formula 2-7);

[0027] 86≤m≤125 (Formula 1-8), (Formula 2-8).

[0028] The preparation steps of the silicone oil concentrated composition of the present invention introduce the specific preparation process of the silicone oil concentrated composition containing two hydrogen atoms at both ends, including the steps of raw material addition amount, catalyst, reaction conditions, post-treatment, etc. A specific technical scheme is adopted, including mixing and stirring methyl cyclic siloxane, hydrogen-containing cyclic siloxane and linear siloxane or methyl linear siloxane containing hydrogen at the end, adding a catalyst for condensation reflux and heating, and then adding a specific substance to terminate its reaction and removing the solvent and low-boiling water, etc., to prepare an oily concentrated defoamer composition, the method is simple and the cost is low. Compared with the commercially available defoamers based on polyether-modified organic silicone oil, the present invention only needs one-step synthesis to obtain an oil concentrated composition, and the inhibitory ability of some examples is the same as or better than that of the commercially available defoamers, reducing costs while ensuring performance. The relatively simple preparation method of the silicone oil concentrated composition helps to reduce the production cost of the entire defoamer compared to some complex multi-step production processes. At the same time, under the premise of ensuring the defoaming performance, the cost performance of the product is improved, so that it has certain advantages in market competition.

[0029] The present invention optimizes the structure of the silicone oil concentrated composition: by adjusting the chain length m and the ratio of m to n, an oily concentrated antifoaming agent composition with different structures and chain lengths is prepared, and the optimizability of this structure can be adjusted according to actual needs to improve the antifoaming ability and storage stability.

[0030] Furthermore, the silicone oil concentrated composition of formula 1 is prepared by:

[0031] S11 Solution preparation: In a container, add octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane considering the ratio of m to n, and add tetramethyldisiloxane according to the chain length;

[0032] S12 catalyst addition: add 1-5% of the total mass of concentrated sulfuric acid as a catalyst, condense and reflux under nitrogen environment and heat and stir, the reaction temperature is controlled at 50-70°C, and the polymerization reaction lasts for 4-7 hours;

[0033] S13 cooling and neutralization: adding solid sodium carbonate for neutralization to terminate the reaction, stirring until the pH value reaches neutral, and cooling naturally to room temperature;

[0034] S14 Filtration and distillation: Filter the neutralized solid matter, and distill under reduced pressure at 70-90° C. for 3-5 hours to evaporate the low-boiling point substances to obtain a transparent liquid product, a silicone oil concentrated composition of Formula 1.

[0035] Furthermore, the silicone oil concentrated composition of formula 2 is prepared by:

[0036] S21 solution preparation: In a container, add octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane considering the ratio of m to n, and add hexamethyldisiloxane according to the chain length;

[0037] S22 catalyst addition: add 1-5% of the total mass of concentrated sulfuric acid as a catalyst, condense and reflux under nitrogen environment and heat and stir, the reaction temperature is controlled at 50-70°C, and the polymerization reaction lasts for 4-7 hours;

[0038] S23 cooling and neutralization: adding solid sodium carbonate for neutralization to terminate the reaction, stirring until the pH value reaches neutral, and naturally cooling to room temperature;

[0039] S24 Filtration and distillation: Filter the neutralized solid matter, and distill under reduced pressure at 70-90° C. for 3-5 hours to evaporate the low-boiling point substances to obtain a transparent liquid product, a silicone oil concentrated composition of Formula 2.

[0040] Octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane are key raw materials for constructing the basic structure of the silicone oil concentrate composition. Their combination and addition with tetramethyldisiloxane in a specific ratio provide a suitable chemical structure basis for subsequent reactions, determine the chain length distribution and chemical properties of the final product, and thus affect its performance in the defoamer. Different chain lengths and proportions will cause differences in the defoaming ability, stability, etc. of the silicone oil concentrate composition to meet the needs of different oily systems. Hexamethyldisiloxane is added instead of tetramethyldisiloxane according to the chain length, which makes Formula 2 different from Formula 1 in structure. This structural difference will lead to differences in its chemical properties and physical properties, which in turn affects the mode of action and effect in the defoamer. It exhibits unique characteristics in terms of interaction with the oily system, the mechanism of suppressing bubbles, and compatibility with other ingredients, providing more options for meeting the defoaming needs of different oily systems.

[0041] Concentrated sulfuric acid, as a catalyst, can reduce the activation energy of the reaction and accelerate the polymerization reaction. Condensation reflux and heating and stirring are carried out in a nitrogen environment. Nitrogen plays a protective role to prevent the raw materials and products from being oxidized, ensure the stability of the reaction environment, and avoid the introduction of impurities that affect the product quality. The precise control of the reaction temperature at 50-70°C and the polymerization reaction for 4-7 hours is to make the reaction proceed under appropriate kinetic conditions, ensure that the raw materials react fully, and generate a silicone oil concentrated composition with the expected structure and performance. Too high temperature or too long time will lead to an increase in side reactions and affect product quality; too low temperature or too short time will make the reaction incomplete and the product performance poor. Accurate control of reaction conditions is crucial to ensure the consistency of product quality and performance, so that the prepared formula 1 and formula 2 can stably play their role in the antifoaming agent system and achieve repeatable performance in mass production.

[0042] Add solid sodium carbonate to neutralize the concentrated sulfuric acid, stop the reaction, and adjust the pH value of the system to neutral. This step is crucial because the residual acidic substances will have a negative impact on the stability, corrosiveness and compatibility of the product with other ingredients. Natural cooling to room temperature provides suitable temperature conditions for subsequent filtration operations, which is convenient for operation. It also helps to stabilize the product structure, avoid structural changes or performance fluctuations caused by sudden temperature changes, ensure that the product is in the best condition before entering the next process, facilitate the subsequent filtration and distillation operations, and improve the overall quality of the product.

[0043] The solid matter after filtering and neutralization can remove insoluble impurities generated during the reaction, such as unreacted catalysts, salts generated by neutralization, etc., improve the purity of the product, and provide a pure raw material basis for subsequent applications. Reduced pressure distillation at 70-90°C for 3-5 hours can effectively evaporate low-boiling point substances, further purify the product, and remove impurities such as residual solvents and unreacted small molecule raw materials. The obtained transparent liquid product silicone oil concentrated composition formula 1 and formula 2 has higher purity and more stable performance. It can better play its role in the antifoam formulation, such as more effectively reducing surface tension, improving synergy with other ingredients, etc., thereby improving the overall performance of the antifoam, ensuring stability during storage and use, and extending the service life and effectiveness of the antifoam product.

[0044] The silicone oil concentrate composition prepared in the process of the present invention has 16 different types, which can accurately adapt to the needs of different oily systems, optimize the anti-foaming performance, improve the flexibility and adaptability of the product, and achieve performance balance and optimization.

[0045] Preferably, the silicone oil concentrate composition has 8 siloxanes based on the m:n ratio in each structural formula of Formula 1 and Formula 2 according to different chain lengths, and a total of 16 siloxanes, thereby obtaining 16 silicone oil concentrate compositions.

[0046] Formula 1 and Formula 2 show the oily foam suppressor concentrate composition used in the present invention, which is distinguished by whether the terminal group of the polymer is hydroxyl or methyl; and is further divided into 16 groups according to the chain length of m in the oily foam suppressor concentrate composition and the ratio of m to n:

[0047] a The dynamic viscosity of formula 1-1, 1-5, 2-1, 2-5 is 10 to 40 cSt, preferably 15 to 29 cSt;

[0048] b. The dynamic viscosity of formula 1-2, 1-6, 2-2, 2-6 is 40 to 120 cSt, preferably 42 to 117 cSt;

[0049] c. The dynamic viscosity of formula 1-3, 1-7, 2-3, 2-7 is 90 to 200 cSt, preferably 99 to 183 cSt;

[0050] d. The dynamic viscosity of formula 1-4, 1-8, 2-4, 2-8 is 120 to 500 cSt, preferably 130 to 437 cSt.

[0051] Different oil systems differ in viscosity, composition, foaming characteristics, etc. The 16 silicone oil concentrates are based on the diversity of chain lengths and ratios, which can be more accurately adapted to various oil systems. Some high-viscosity oil systems require silicone oil concentrates with specific chain lengths and ratios to achieve the best anti-foaming effect, and these 16 different combinations provide a wide range of choices, ensuring that the most suitable formula for a specific oil system can be found, thereby improving the effectiveness of the anti-foam agent in different application scenarios.

[0052] Changes in chain length and ratio affect the chemical structure and physical properties of the silicone oil concentrate, which in turn affects its anti-foaming performance. By providing 16 different siloxane combinations, the anti-foaming ability of the anti-foam agent can be adjusted according to specific needs. Some combinations perform well in suppressing bubble generation, while others are more advantageous in stabilizing formed foam or accelerating bubble collapse. This diversity makes it possible to select the most suitable silicone oil concentrate to achieve optimized anti-foaming performance and improve anti-foaming efficiency and effectiveness based on the characteristics of foam in different oil systems.

[0053] In the market, there are many types of oily systems and they are constantly changing. With 16 kinds of silicone oil concentrates, the antifoam products have higher flexibility and adaptability. Whether it is an existing oily system or a new oily system that may appear in the future, it is more likely to find a suitable silicone oil concentrate to match and produce an antifoam that meets the needs. This helps the product to be more widely used in different industries and application fields, enhances the market competitiveness of the product, and also provides users with more customized solutions.

[0054] While considering the anti-foaming performance, other properties need to be taken into account, such as storage stability, compatibility with oily systems, etc. The existence of 16 silicone oil concentrate compositions allows for trade-offs and optimization between different properties. Some combinations achieve a better balance between anti-foaming performance and storage stability, while others excel in anti-foaming performance and compatibility with specific oily systems. By selecting the appropriate silicone oil concentrate composition, the overall performance can be optimized according to the key requirements of specific applications, thereby improving the overall quality and practicality of the product.

[0055] The filler is treated with hydrophobicity, which helps to improve the performance of the antifoam agent in complex environments and is different from other conventional antifoam agent ingredients.

[0056] Preferably, the hydrophobic treated filler is hydrophobic treated fumed silica or nano-silicon dioxide, with a specific surface area of ​​70-150m 2 / g, and the proportion in the novel silicone antifoam component is maintained at 5-20wt%.

[0057] Selecting hydrophobic treated fumed silica or nano-silica and controlling its parameters can enhance the dispersibility requirements, adapt to the characteristics of the oily system, optimize the anti-foaming performance, balance the initial defoaming and foam breaking capabilities, and maintain the stability of the system structure.

[0058] The specific surface area of ​​70-150m² / g provides a rich surface active site for the filler, which can interact strongly with other ingredients such as silicone oil concentrate, high viscosity polydimethylsiloxane and fatty alcohol and propylene oxide polymer, so that the filler is more evenly dispersed in the entire antifoam system. Evenly dispersed fillers can avoid agglomeration, ensuring that they can play their role in suppressing foam at all positions in the oily system, thereby improving the overall effectiveness of the antifoam agent. If the specific surface area is too small, the active sites are insufficient, which may lead to uneven dispersion; if the specific surface area is too large, the filler itself may aggravate agglomeration, which is also not conducive to dispersion.

[0059] For oily media, especially high-viscosity oily systems, hydrophobic treatment is the key, which can make the surface properties of the filler match the oily environment and enhance its compatibility with the oily system. In such a system, the filler can be better integrated into it, reducing adverse phenomena such as precipitation and stratification caused by incompatibility, thereby improving the stability and applicability of the antifoaming agent in the oily system, enabling it to effectively inhibit the generation of bubbles in the oily system.

[0060] Fillers work together with other ingredients to destroy the stability of bubbles and accelerate bubble rupture. Fumed silica or nano-silica particles can be adsorbed on the surface of the bubble film, changing the local surface tension of the bubble film, causing the bubble film to become thinner until it ruptures. Maintaining its proportion in the new silicone foam suppressant component at 5-20wt% is the optimal range obtained after a lot of experiments and research. Within this range, it can ensure that there is enough filler to effectively suppress foam, but it will not interfere with the synergistic effect of other ingredients due to excessive content, or cause the system to be too viscous, affecting its dispersion and function in the oily system.

[0061] The characteristics of the filler after hydrophobic treatment help to quickly take effect in the early stage of foam generation and enhance the initial defoaming ability. During the foam formation process, it can effectively destroy the bubble structure and improve the defoaming property. This is because the appropriate specific surface area and hydrophobic treatment enable the filler to quickly contact the newly formed bubbles and interfere with the stable existence of the bubbles, while the control of the ratio ensures the balance and continuity of this ability throughout the defoaming process, so that the defoamer can effectively control the foam at different stages.

[0062] A specific proportion of fillers in the defoamer system helps maintain the stability of the overall structure. Together with other ingredients, it builds a relatively stable microstructure to prevent the separation and precipitation of ingredients, ensuring the performance consistency of the defoamer during storage and use. A stable system structure can ensure that the defoamer can play an effective role for a long time, extend the service life of the product, and enable it to reliably suppress the generation of foam in oily systems in various application scenarios.

[0063] The hydrophobic treatment method imparts hydrophobicity to the filler, improves the synergistic effect between the filler and other ingredients, enhances the anti-foaming performance of the filler, and optimizes the physical and chemical properties of the filler.

[0064] Furthermore, the hydrophobic treatment method is: under the action of the prepared silicone oil composition, heating the fumed silica or nano-silica to 100 to 300°C for 2-5 hours to make it hydrophobic, and the ratio of the silicone oil composition to the fumed silica or nano-silica is 1:5-20.

[0065] Under the action of the prepared silicone oil composition, heating the fumed silica or nano-silicon dioxide to 100 to 300°C for 2-5 hours can change the chemical properties of the filler surface, thereby obtaining hydrophobicity. This hydrophobicity makes the filler more compatible in the oily system, can better integrate into the oily medium, reduce the precipitation and agglomeration problems caused by incompatibility with the oily system, improve the stability and dispersibility of the antifoaming agent in the oily system, and thus enhance the overall performance of the antifoaming agent.

[0066] After the hydrophobic treatment, the properties of the filler surface are more compatible with other ingredients such as the silicone oil concentrate, high viscosity polydimethylsiloxane, and fatty alcohol and propylene oxide polymer. This helps the filler to better cooperate with other ingredients in the foam suppressor system and jointly play the role of suppressing foam. In the process of suppressing bubble generation and stabilizing foam, the hydrophobic filler can cooperate with other ingredients to more effectively change the surface tension and interface properties of the system and improve the foam suppression effect.

[0067] When the hydrophobic filler comes into contact with bubbles, its surface properties can reduce the stability of the bubble film and accelerate the rupture of the bubbles. The filler particles can be adsorbed on the surface of the bubble film. Due to its hydrophobicity, the local surface tension distribution of the bubble film is changed, making the bubble film easier to thin and rupture, thereby improving the anti-foaming performance of the filler in the anti-foaming agent, especially in high-viscosity oily systems, this performance improvement is more obvious, which helps to better meet the anti-foaming needs in practical applications.

[0068] The heating and silicone oil composition process not only imparts hydrophobicity to the filler, but also has other beneficial effects on its physical and chemical properties. The heat is used for dehydration reaction and hydrophobic treatment, and the Si-OH or Si-O-Si in the silicone oil concentrated composition reacts with the Si-OH in the fumed silica or nano-silicon dioxide to form a chemical bond. This chemical bond effect makes the silicone oil concentrated composition more firmly cross-linked on the filler surface and the surface hydrophobicity is stable, which means that the compatibility of the filler in the oily system is enhanced, and it can be better integrated into the oily medium, reducing precipitation, agglomeration and other problems. In addition to the stable hydrophobicity, this process changes the surface morphology, pore structure, etc. of the filler, further increases its specific surface area or active sites, which enables the filler to play a better role in the antifoam system and improves the comprehensive performance of the antifoam. At the same time, it also improves the temperature resistance, chemical resistance and other properties of the filler, broadens its application range under different conditions, and in practical applications, the treated filler can adapt to more complex oily system environments and effectively inhibit the generation of foam. The heating and the action of the silicone oil composition make the surface properties of the filler more compatible with the oily system, thereby improving the dispersibility of the filler in the oily system. The evenly dispersed filler can avoid agglomeration, ensuring that it can play its role in suppressing foam at all positions in the oily system, thereby improving the overall effectiveness of the antifoam agent; the change in the surface properties of the filler enhances its synergistic effect with other ingredients such as the silicone oil concentrated composition, high-viscosity polydimethylsiloxane and fatty alcohol and propylene oxide polymer, and in the process of suppressing bubble generation and stabilizing foam, it can more effectively change the surface tension and interfacial properties of the system and improve the antifoam effect; the enhancement of the synergistic effect helps to maintain the stability of the overall structure of the antifoam agent system, prevent the separation and precipitation of the components, and ensure the performance consistency of the antifoam agent during storage and use, which enables the antifoam agent to play its role effectively for a long time and extend the service life of the product.

[0069] When preparing the hydrophobic treated filler in the process of the present invention, the filler is evenly dispersed in the silicone oil concentrated composition, thereby enhancing the hydrophobicity, dispersibility, stability and compatibility of the filler with other components; strictly controlling the reaction conditions to ensure stable and consistent performance of the filler, thereby improving the reliability of product quality; centrifugal separation can remove impurities, recover unreacted filler, improve raw material utilization, reduce costs, reduce waste emissions, and bring economic and environmental benefits; and provide a basis for optimizing the antifoaming agent formula, which is conducive to flexible adjustment of the formula to achieve the best antifoaming effect and meet different needs.

[0070] Furthermore, the preparation method of the hydrophobically treated filler is:

[0071] a. Mixing the filler with the silicone oil concentrated composition: adding the hydrophobized fumed silica or nano-silicon dioxide to the prepared silicone oil concentrated composition in a ratio of 1:8-70, and mixing and stirring;

[0072] b. Reaction and heating: heating the mixture to 150-180° C. and reacting for 6-8 hours under stirring to obtain a hydrophobic treated filler having a silicone oil concentrated composition on its surface;

[0073] c. Treatment after the reaction is completed: the hydrophobic treated filler containing the silicone oil concentrated composition on the surface is directly stored and kept without centrifugation, the unused filler is used after centrifugal separation and drying, and the unreacted silicone oil concentrated composition is collected and recycled.

[0074] In the preparation method of the hydrophobic treated filler, the hydrophobic treated fumed silica or nano-silicon dioxide is mixed and stirred with the silicone oil concentrate composition at a specific ratio of 1:8-70. This step is intended to allow the filler surface to fully contact the silicone oil concentrate composition. On the one hand, the silicone oil concentrate composition can further modify and modify the filler to a certain extent, enhancing the compatibility of the filler with the subsequent added components; on the other hand, the initial mixing of the two provides a uniform reaction system for the subsequent reaction, ensuring that the filler is evenly dispersed in the entire system, so that each filler particle has the opportunity to participate in the reaction, thereby laying the foundation for obtaining a hydrophobic treated filler with stable performance and uniformity.

[0075] The mixture is heated to 150-180°C and stirred for 6-8 hours. This process causes a chemical reaction or physical interaction between the silicone oil concentrate composition and the hydrophobized filler. High temperature and stirring conditions help accelerate the reaction process, allowing the silicone oil concentrate composition to better coat the filler surface and form a stable structure. This surface treatment can further improve the hydrophobicity of the filler, enhance its dispersibility and stability in the oily system, and make the combination between the filler and the silicone oil concentrate composition more solid, thereby improving the comprehensive performance of the filler in the defoamer, making it more effective in suppressing foam generation and stabilizing foam.

[0076] The centrifugal separation step is mainly to collect the hydrophobic treated filler with the silicone oil concentrated composition on the surface obtained after the reaction, and to recover the unreacted silicone oil concentrated composition. The collected filler can be directly used in the subsequent preparation of the antifoam agent, ensuring the consistency of product quality and performance. Recycling unused fillers and silicone oil compositions improves the utilization rate of raw materials, reduces production costs, and is also beneficial to environmental protection and reduces waste emissions. In addition, centrifugal separation can remove impurities or agglomerates that may be generated during the reaction, further purify the hydrophobic treated filler, improve its purity and quality, and enable it to play a better role in the antifoam agent system.

[0077] The novel silicone foam suppressor production process provided by the present invention mixes a hydrophobically treated filler, a silicone oil concentrated composition, a high-viscosity polydimethylsiloxane and a non-ionic surfactant in a specific proportion, and the components work synergistically to improve the foam suppression and defoaming capabilities; the clear component ratio range enables it to be accurately formulated according to the needs of the oily system, enhances the versatility and practicality of the product, and can effectively deal with foam problems in different scenarios; reasonable raw material selection and ratio design reduce production costs, improve production efficiency, and make the product more competitive in the market; the prepared foam suppressor can be widely used in a variety of oily foaming liquid systems, especially performs well in high-viscosity oily systems, and can effectively solve the foam problems of different oily systems.

[0078] The present invention provides a production process of a novel silicone foam suppressor, the specific steps of which are:

[0079] 1-5 parts of a hydrophobically treated filler are mixed with 40-70 parts of a silicone oil concentrate composition and stirred, 40-70 parts of a high-viscosity polydimethylsiloxane and 100-150 parts of a nonionic surfactant are further added, and stirred at a high speed, oleic acid is added to the stirred basic formula of the foam suppressor, and heated to react, thereby obtaining a novel silicone foam suppressor.

[0080] The production process of the silicone foam suppressor of the present invention comprises the following steps: mixing a hydrophobic treated filler, a silicone oil concentrated composition, a high-viscosity polydimethylsiloxane and a nonionic surfactant in a specific ratio, wherein the components work synergistically to effectively suppress the generation of foam in an oily system; the hydrophobic treated filler helps to destroy the stability of bubbles, the silicone oil concentrated composition can change the surface tension of the system, the high-viscosity polydimethylsiloxane enhances the stability of the system, and the nonionic surfactant improves the dispersibility of the components, and the foam suppression and defoaming capabilities are jointly improved, thereby obtaining a high-performance foam suppressor that meets the foam suppression requirements of various oily systems.

[0081] The mixing and stirring steps ensure that all ingredients are evenly mixed, providing a good foundation for subsequent reactions. High-speed stirring further promotes full contact and interaction between the ingredients to form a stable system, effectively prevents component separation, and ensures the stability of the antifoaming agent performance. The heating reaction causes chemical reactions or physical interactions between the ingredients, which enhances the binding force between them, further improves the stability of the product, prolongs the storage time of the product, and reduces the possibility of performance fluctuations during storage.

[0082] Oleic acid, a natural degradable ingredient, is introduced and combined with silicone. Oleic acid, as an unsaturated fatty acid, has good emulsification and dispersibility, which can improve the dispersion effect of the antifoaming agent in the foaming system and enable the antifoaming agent to work more evenly. At the same time, oleic acid itself is easily decomposed by microorganisms in nature. After combining with silicone, it can improve the degradability of the entire antifoaming agent system to a certain extent.

[0083] The clear range of ingredient ratios and specific process steps allow the process to be adjusted according to the characteristics of different oily systems, thereby preparing an antifoaming agent suitable for a variety of oily foaming liquid systems and improving the applicability of the product; the antifoaming agent can exert a good antifoaming effect in both low-viscosity and high-viscosity oily systems and has a wide range of applicability; especially in high-viscosity oily systems, its performance advantages are more prominent, and it can effectively solve the foam problem that is prone to occur in high-viscosity oily systems, providing an effective foam control solution for the coatings, inks, lubricants and other industries.

[0084] The process steps of the invention are relatively simple, easy to operate and control, do not require complicated equipment and harsh reaction conditions, optimize the production process, and are conducive to large-scale production; reasonable raw material selection and proportion design not only ensure the performance of the product, but also reduce the production cost; in the production process, each component can be fully utilized, reducing the waste of raw materials, improving production efficiency, making the product more competitive in the market, and also complying with the principle of sustainable development, bringing economic and environmental benefits to the enterprise.

[0085] At the same time, the process can adjust the performance of the antifoaming agent by adjusting the type and proportion of raw materials; by changing the structure and chain length of the silicone oil concentrate composition, selecting different types of non-ionic surfactants, etc., the antifoaming agent can be adapted to different usage environments and special needs, such as improving high temperature resistance and chemical resistance; this performance adjustment capability enables the antifoaming agent to meet diverse market demands, expand the application range of the product, and play an important role in different fields and industries.

[0086] Nonionic surfactants have good compatibility and dispersibility, can reduce surface tension and are stable; oleic acid can enhance anti-foaming performance while balancing performance and cost.

[0087] Preferably, the nonionic surfactant is a polymer of fatty alcohol and propylene oxide, has a neutral pH value, and a hydroxyl value less than or equal to 35 mgKOH / g; and the amount of oleic acid used accounts for 0.5-3.0% of the total mass of the antifoaming agent.

[0088] The polymer of fatty alcohol and propylene oxide is a nonionic surfactant. Its molecular structure makes it have good compatibility in oily systems, and it can be better mixed with other ingredients to avoid agglomeration or stratification, which helps to improve the stability of the antifoaming agent in the oily system and ensure that it can continue to effectively play an antifoaming role during use. At the same time, the good dispersibility enables the active agent to be evenly distributed in the system, giving full play to its surface activity, and further enhancing the antifoaming effect. The polymer has a low surface tension and can effectively reduce the surface energy of the oily system, making it difficult for bubbles to exist stably in the early stage of formation, thereby improving the ability of the antifoaming agent to inhibit the generation of bubbles. In addition, its pH value is neutral, and it will not have a significant impact on the acidity and alkalinity of the oily system during use, ensuring the chemical stability of the system. The characteristic of hydroxyl value less than or equal to 35 mgKOH / g helps to control the balance between the hydrophilicity and lipophilicity of the surfactant, so that it can play an effective role in the oily system without affecting the overall performance due to excessive hydrophilicity, further enhancing its applicability and stability in the antifoaming agent.

[0089] The amount of oleic acid accounts for 0.5-3.0% of the total mass of the defoamer. Within this range, oleic acid can work synergistically with other ingredients to further optimize the performance of the defoamer. Oleic acid molecules have a special structure and can form an adsorption layer on the surface of bubbles, change the surface properties of bubbles, and make the bubble membrane easier to break, thereby improving the defoaming and defoaming capabilities of the defoamer. The addition of an appropriate amount of oleic acid can make up for the deficiencies of other ingredients in inhibiting bubbles and form a more complete defoaming system. By accurately controlling the amount of oleic acid between 0.5-3.0%, not only can a good defoaming effect be achieved, but also the production cost can be reasonably controlled while ensuring product performance. When the amount of oleic acid is too small, its synergistic effect cannot be fully exerted, affecting the overall performance of the defoamer. Excessive use will lead to increased costs, and also have a negative impact on other properties of the product, affecting the stability or compatibility of the system. Therefore, optimizing the amount of oleic acid can find the best balance between performance and cost, improve the cost performance of the product, and make it more competitive in the market.

[0090] The present invention provides an effective method for preparing a concentrated defoamer composition based on factors such as hydrogen content and structural length, uses siloxane as a defoamer composition, and provides a method for preparing a siloxane-based defoamer, which is easy to manufacture and low in cost, and has an excellent defoaming effect, especially in a high-viscosity oil-based system, and can be used in all oily foaming liquid systems, especially high-viscosity oily systems, solving the problems of poor compatibility and insufficient defoaming ability of traditional defoamers in some cases. The novel siloxane defoamer production process of the present invention prepares the defoamer by mixing a hydrophobic treated filler, a silicone oil concentrated composition, a high-viscosity polydimethylsiloxane and a fatty alcohol with a propylene oxide polymer through specific mixing, stirring and heating reaction steps. This multi-component synergistic reaction production process design fully considers the interaction between the components, and can produce a novel defoamer with excellent performance, which is different from the traditional defoamer production process of simply mixing components. The filler treated with hydrophobic treatment has lower surface tension than general polydimethylsiloxane, and has the easy dispersion characteristics of non-ionic surfactants. It can be blended with high-viscosity polysiloxane to enhance the defoaming and degassing ability and stability, as well as the stability, compatibility, dispersibility, high temperature resistance, resistance to hydroxyl groups and inorganic salts in oil and oily fluids, and can be used for anti-foaming under difficult conditions.

[0091] In summary, the present invention has the following beneficial effects:

[0092] 1. During the synthesis of the novel silicone antifoaming agent of the present invention, the antifoaming performance is optimized by using a silicone oil concentrate composition. The silicone oil concentrate composition forms 16 different types according to the chain length and ratio, which can be accurately adapted to various oil systems. The combination of different chain lengths and ratios makes the chemical structure and physical properties of the composition diverse, and each has its own advantages in inhibiting bubble generation, stabilizing foam or accelerating bubble rupture. It can be selected according to the foaming characteristics of different oil systems, improve the antifoaming efficiency and effect, enhance the applicability of the product in different fields and industries, and enhance market competitiveness;

[0093] 2. The synthesis of the novel siloxane foam suppressor of the present invention helps to suppress foam by improving the performance of the filler. The hydrophobic treated filler is hydrophobicized fumed silica or nano-silica, which has an appropriate specific surface area, enhances dispersibility at a specific ratio, has good compatibility with the oily system, reduces precipitation and stratification, and cooperates with other ingredients to destroy the stability of bubbles, enhances the initial defoaming and breaking ability, and maintains the stability of the system structure;

[0094] 3. The production process of the novel silicone foam suppressor of the present invention improves the overall performance by adding nonionic surfactants and oleic acid. The nonionic surfactants make the components well dispersed, reduce surface tension, ensure the chemical stability of the system, and improve the applicability and stability of the foam suppressor; oleic acid improves the dispersion effect, improves the degradability, and synergistically optimizes the foam suppression performance; the overall production process is simple and easy to control, can be adjusted as needed, is applicable to a variety of oily systems, has outstanding advantages in high-viscosity oily systems, and effectively solves the foam problem;

[0095] 4. In the synthesis and production process of the novel silicone foam suppressant of the present invention, reasonable raw material selection and process design reduce costs and improve production efficiency; centrifugal separation during filler preparation can recycle unreacted fillers, improve raw material utilization, reduce waste emissions, and bring economic and environmental benefits;

[0096] 5. The present invention provides a synthesis and production process of a novel silicone antifoam agent, wherein the preparation method of the silicone oil concentrate composition is simple, the product has high purity, stable performance, and good compatibility with other ingredients, thereby ensuring the quality and stability of the antifoam agent, preventing adverse phenomena such as phase separation, and extending the service life and effectiveness of the product; the various components of the antifoam agent synergistically construct a stable microstructure, prevent component separation and precipitation, ensure consistent storage and use performance, effectively inhibit the generation of foam in oily systems for a long time, and provide users with a reliable and long-lasting foam control solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Figure 1 It is a schematic diagram of the evaluation results of the antifoaming ability of each group of antifoaming agents. DETAILED DESCRIPTION

[0098] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

[0099] 1. Experimental Methods

[0100] 1.1 Preparation of silicone oil concentrated composition

[0101] 1.1.1 Preparation of silicone oil concentrated composition Formula 1

[0102] The first silicone oil concentrated composition 1 having hydrogen atoms at both ends is prepared by:

[0103] S11 In a 500 ml four-necked flask under nitrogen, octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane were first added, and then tetramethyldisiloxane was added according to the chain length;

[0104] S12 adds 2% concentrated sulfuric acid as a catalyst, condenses and refluxes under nitrogen environment and heats and stirs. The reaction temperature is controlled at 50-70°C and the polymerization reaction lasts for 4-7 hours.

[0105] S13 adds solid sodium carbonate to neutralize, ends the reaction, stirs until the pH value reaches neutral, and cools naturally to room temperature;

[0106] S14 Filter the neutralized solid matter, and distill under reduced pressure at 70-90° C. for 3-5 hours to evaporate the low-boiling point substances to obtain a transparent liquid product, silicone oil concentrated composition 1, whose chemical formula is as follows. The addition amount of the methyl silicone oil concentrated composition in different embodiments is shown in Table 1 below:

[0107]

[0108] Table 1 Examples of silicone oil concentrate compositions based on m:n ratio and chain length with hydrogen atoms at the end

[0109] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Octamethylcyclotetrasiloxane / wt% 68.93 82.77 76.16 93.25 77.21 94.99 77.77 95.67 Tetramethylcyclotetrasiloxane / wt% 29.02 2.24 20.38 2.52 20.69 2.58 20.81 2.60 Tetramethyldisiloxane / wt% 12.50 14.99 3.46 4.23 2.10 2.43 1.42 1.73 Chemical formula Formula 1-1 Formula 1-5 Formula 1-2 Formula 1-6 Formula 1-3 Formula 1-7 Formula 1-4 Formula 1-8

[0110] 1.1.2 Preparation of silicone oil concentrated composition Formula 2

[0111] The second silicone oil concentrated composition 2 containing hydrogen atoms at both ends is prepared by:

[0112] S21 In a 500 ml four-necked flask under nitrogen, octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane were first added, and then hexamethyldisiloxane was added according to the chain length;

[0113] S22 adds 2% concentrated sulfuric acid as a catalyst, condenses and refluxes under nitrogen environment and heats and stirs. The reaction temperature is controlled at 50-70°C and the polymerization reaction lasts for 4-7 hours.

[0114] S23 adds solid sodium carbonate to neutralize, ends the reaction, stirs until the pH value reaches neutral, and cools naturally to room temperature;

[0115] S24 Filter the neutralized solid matter, and distill under reduced pressure at 70-90°C for 3-5 hours to evaporate the low-boiling point substances to obtain a transparent liquid product, silicone oil concentrated composition 2, whose chemical formula is as follows. The addition amount of the methyl silicone oil concentrated composition in different embodiments is shown in Table 2 below:

[0116]

[0117] Table 2 Examples of silicone oil concentrate compositions based on m:n ratio and chain length with methyl groups at the end

[0118] Example 9 Example 10 Embodiment 11 Example 12 Example 13 Embodiment 14 Embodiment 15 Example 16 Octamethylcyclotetrasiloxane / wt% 67.87 68.26 75.63 94.83 76.88 94.51 77.55 96.33 Tetramethylcyclotetrasiloxane / wt% 17.39 1.85 20.23 2.57 20.6 2.56 79.25 2.66 Hexamethyldisiloxane / wt% 14.74 29.89 4.14 2.60 2.52 2.93 1.70 1.01 Chemical formula Formula 2-1 Formula 2-5 Formula 2-2 Formula 2-6 Formula 2-3 Formula 2-7 Formula 2-4 Formula 2-8

[0119] 1.2 Preparation of filler

[0120] The hydrophobic treatment method is: under the action of the prepared silicone oil composition, the fumed silica or nano-silicon dioxide is heated to 100 to 300°C for 2-5 hours to make it hydrophobic, and the ratio of the silicone oil composition to the fumed silica or nano-silicon dioxide is 1:10. The preparation method of the hydrophobic treated filler is:

[0121] S31: Mixing the filler with the silicone oil concentrated composition: adding the hydrophobized fumed silica or nano-silicon dioxide to the prepared silicone oil concentrated composition in a ratio of 1:8-70, and mixing and stirring;

[0122] S32 reaction and heating: heating the mixture to 150-180° C. and reacting for 6-8 hours under stirring to obtain a hydrophobic treated filler having a silicone oil concentrated composition on its surface;

[0123] S33 Treatment after completion of the reaction: The hydrophobic treated filler containing the silicone oil concentrated composition on the surface is directly stored and preserved without centrifugation, the unused filler is used after centrifugal separation and drying, and the unreacted silicone oil concentrated composition is collected and recycled.

[0124] 1.3 Preparation of new silicone foam suppressant

[0125] The production process of compounding a novel silicone foam suppressor comprises the following specific steps:

[0126] 1-5 parts of a hydrophobically treated filler and 40-70 parts of a silicone oil concentrate composition are mixed and stirred, and further 40-70 parts of a high-viscosity polydimethylsiloxane and 100-150 parts of a nonionic surfactant are added and stirred at a high speed. Oleic acid is added to the stirring basic formula of the antifoaming agent, and the mixture is heated for reaction to obtain a novel silicone antifoaming agent sample.

[0127] 1.4 Example: Novel Silicone Antifoam Sample

[0128] a. Sample 1: an example of a novel silicone foam suppressor sample prepared by a compounding method using the silicone oil concentrated composition Example 1 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0129] b. Sample 2: an example of a novel silicone foam suppressor sample prepared by a compounding method using the silicone oil concentrated composition Example 2 and mixed with the silicone oil concentrated composition for hydrophobic treatment of silica;

[0130] c. Sample 3: an example of a novel silicone foam suppressor sample prepared by a compounding method using the silicone oil concentrated composition Example 3 and mixed with the silicone oil concentrated composition for hydrophobic treatment of silica;

[0131] d. Sample 4: an example of a novel silicone antifoaming agent sample prepared by a compounding method using the silicone oil concentrated composition Example 4 and mixed with the silicone oil concentrated composition for hydrophobic treatment of silica;

[0132] e. Sample 5: an example of a novel silicone foam suppressant sample prepared by a compounding method using the silicone oil concentrated composition Example 5 and mixed with the silicone oil concentrated composition for hydrophobic treatment of silica;

[0133] f. Sample 6: an example of a novel silicone foam suppressor sample prepared by a compounding method using the silicone oil concentrated composition Example 6 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0134] g. Sample 7: an example of a novel silicone foam suppressant sample prepared by a compounding method using the silicone oil concentrated composition Example 7 and mixed with the silicone oil concentrated composition for hydrophobic treatment of silica;

[0135] h. Sample 8: An example of a novel silicone foam suppressant sample prepared by a compounding method using the silicone oil concentrated composition Example 8 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0136] i. Sample 9: an example of a novel silicone foam suppressant sample prepared by a compounding method using the silicone oil concentrated composition Example 9 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0137] j. Sample 10: an example of a novel silicone foam suppressant sample prepared by a compounding method using the silicone oil concentrated composition Example 10 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0138] k. Sample 11: an example of a novel silicone foam suppressant sample prepared by a compounding method using the silicone oil concentrated composition Example 11 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0139] 1. Sample 12: An example of a novel silicone foam suppressor sample prepared by a compounding method using the silicone oil concentrated composition Example 12 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0140] m. Sample 13: an example of a novel silicone antifoaming agent sample prepared by a compounding method using the silicone oil concentrated composition Example 13 and mixed with the silicone oil concentrated composition for hydrophobic treatment of silica;

[0141] n. Sample 14: an example of a novel silicone antifoaming agent sample prepared by a compounding method using the silicone oil concentrated composition Example 14 and mixed with a silicone oil concentrated composition for hydrophobic treatment of silica;

[0142] o. Sample 15: An example of a novel silicone foam suppressant sample prepared by a compounding method using the silicone oil concentrate composition Example 15 and mixed with a silicone oil concentrate composition for hydrophobic treatment of silica;

[0143] p. Sample 16: An example of a novel silicone antifoaming agent sample prepared by a compounding method and mixed with a silicone oil concentrate composition for hydrophobic treatment of silica using the silicone oil concentrate composition Example 16.

[0144] 1.5 Comparative Example: Non-foam suppressor sample of the present invention

[0145] r. Comparative Example 1 Sample: Add hydrophilic fumed silica or nano-silica to the above-prepared Example 8 to react at a reaction temperature of 150-180°C for 6-8 hours, and heat and stir to obtain a product, which is collected after centrifugation as needed; unused hydrophobically treated fumed silica or nano-silica does not need to be centrifuged and stored, and can be used as needed; the concentrated composition Example 8 and the hydrophobically treated filler are mixed in a flask, stirred, and a polymer of fatty alcohol and propylene oxide is further added, and a high-speed stirring heating reaction is performed to obtain a foam suppressant;

[0146] s. Comparative Example 2 Sample: Add hydrophilic fumed silica or nano-silica to 100000 cSt polydimethylsiloxane for reaction at a reaction temperature of 150-180°C for a reaction time of 6-8 hours, and obtain a product after heating and stirring, which is collected after centrifugation as needed; unused hydrophobically treated fumed silica or nano-silica does not need to be centrifuged and stored, and can be used as needed; 100000 cSt polydimethylsiloxane and a hydrophobically treated filler are mixed in a flask, stirred, and a polymer of fatty alcohol and propylene oxide is further added, and a high-speed stirring and heating reaction is performed to obtain a foam suppressant;

[0147] t. Comparative Example 3 Sample: A commercially available defoamer based on polyether-modified silicone oil, Airex 901W (Evonik), was used. The active ingredients of this product grade of oily defoamer are 100% polyether siloxane copolymer and hydrophilic fumed silica or nano-silica filler.

[0148] 2. Experimental testing

[0149] 2.1 Evaluation of antifoaming ability

[0150] 2.1.1 Criteria for determining foam suppression ability

[0151] Antifoaming ability refers to the ability of the antifoam agent to inhibit the generation of bubbles in a high-viscosity oil-based coating system synthesized from an oily system acrylic resin.

[0152] 2.1.2 Evaluation index representation

[0153] The quantification formula of foam suppression performance f (%) is: , where t0 represents the number of bubbles in the control group, and t1 represents the number of bubbles after adding the inhibitor. The number of bubbles represents the number of bubbles, regardless of their size. The inhibitory ability of the antifoaming agent is evaluated by calculating the value of the antifoaming performance f. The larger the f value, the stronger the antifoaming performance of the antifoaming agent.

[0154] 2.2.3 Specific evaluation operations

[0155] The specific steps for evaluating and testing the foam suppression performance are as follows:

[0156] S41 Take 100g of high-viscosity oil-based paint synthesized from acrylic resin and slowly pour it into a clean and dry beaker, taking care to avoid splashing the paint or mixing in bubbles;

[0157] S42 accurately weighs the defoamer according to 1% of the total mass of the coating, and carefully adds it to the coating in the beaker, wherein the control group does not add the siloxane defoamer;

[0158] S43: Place the stirring blade of the high-speed stirrer into the paint in the beaker, adjust the stirrer to 1000-1500 rpm and stir at high speed for 5-10 minutes to generate microbubbles in the paint; during the stirring process, ensure that the stirring blade is completely immersed in the paint and stir evenly to avoid excessive or insufficient local stirring;

[0159] S44 After stirring, immediately use a dropper or glass rod to dip a small amount of paint, and slowly pour a thin layer of oily paint about 1-2mm thick evenly on the prepared glass plate. Try to avoid generating new bubbles during the operation;

[0160] S45: Place the glass plate on a horizontal and stable desktop. After the coating flows naturally on the glass plate and stabilizes for 1-2 minutes, use a magnifying glass or a low-power microscope to assist in observation, and use manual counting or image analysis software to accurately measure the number of bubbles on the glass plate, and record the number of bubbles at this time t1, wherein the number of bubbles in the control group is recorded as t0; calculate the anti-foaming performance f value according to the following formula, which is the quantitative result of the anti-foaming performance of the new siloxane anti-foaming agent under the experimental conditions of this experiment, and evaluate the storage stability of Example Samples 1-16 and Comparative Examples 1-3, and record their corresponding anti-foaming performance indicators. The evaluation results of the anti-foaming ability of each group of anti-foaming agents are shown in Figure 1 .

[0161]

[0162] 2.2 Storage stability evaluation

[0163] 2.2.1 Stability criteria

[0164] Stable means that the ingredient will not phase separate from the surrounding environment within 3 months.

[0165] 2.2.2 Evaluation index representation

[0166] The symbol [◎] indicates excellent storage stability, which means that not only will phase separation not occur within 3 months, but good stability can also be maintained for a longer period of time;

[0167] The symbol [○] indicates that phase separation does not occur within 3 months, but obvious phase separation gradually occurs when stored for more than 3 months;

[0168] The symbol [X] indicates that phase separation occurred within 3 months.

[0169] 2.2.3 Specific evaluation operations

[0170] Storage stability evaluation test, the specific operations are as follows:

[0171] Observe whether phase separation occurs during storage without artificially changing the external environment, and then evaluate and record the storage stability of the samples according to the above standards and symbols. Perform storage stability evaluation on samples 1-16 and comparative examples 1-3, and record their corresponding storage stability indicators. The results are shown in Table 3 below.

[0172] Table 3 Storage stability evaluation

[0173]

[0174] 2.3 Evaluation of spreadability

[0175] 2.3.1 Spreadable Criteria

[0176] Spreadability refers to the ease with which the antifoaming agent can be applied as a coating on the surface to be coated and the quality characteristics of the coating formed after coating.

[0177] 2.3.2 Evaluation index representation

[0178] By observing the surface of the coating after application, check whether there are defects such as brush marks, orange peel, sagging, shrinkage holes, bubbles, etc. as the spreadability index, and record the severity of each defect, including none, slight, moderate, and severe.

[0179] 2.3.3 Specific evaluation operations

[0180] The specific steps for evaluation of smearability are as follows:

[0181] S51 Prepare several test plates with the same material, size and flatness, and evenly apply the coating sample containing the antifoaming agent on these test plates to ensure that the coating thickness is basically consistent;

[0182] S52 Under normal lighting conditions, observe the surface of the coating after application from different angles such as vertical and 45 degrees to check whether there are defects such as brush marks, orange peel, sagging, shrinkage holes, bubbles, etc.; record the severity of each defect as none, slight, moderate, or severe;

[0183] S53 conducts a comprehensive evaluation based on the observed defects; if the coating surface is smooth and flat with no obvious visible defects, the spreadability is good; if there are a few minor defects, the spreadability is good; if there are many and serious defects, the spreadability is poor. Samples 1-16 and comparative examples 1-3 were evaluated for spreadability, and their corresponding spreadability indicators were recorded. The results are shown in Table 4 below.

[0184] Table 4 Evaluation of spreadability

[0185]

[0186] 3. Results Analysis

[0187] 3.1 Analysis of antifoaming ability evaluation data

[0188] The antifoaming performance f values ​​of Examples 1-16 are mainly concentrated in the relatively high range of 90%-97%, among which some samples such as Sample 9 is 96.96%, Sample 10 is 95.26%, and Sample 11 is 92.05%, all of which show extremely high antifoaming performance. Only the antifoaming performance of Sample 16 is relatively low at 87.03%. The calculation shows that the average antifoaming performance of Examples 1-16 is 93.65%, indicating that the novel siloxane antifoam agent of the present invention has a generally strong ability to inhibit the generation of bubbles in the high-viscosity oil-based coating system synthesized by acrylic resin, most formulations can achieve a relatively high antifoaming level, and there is a certain consistency between the embodiments, indicating that the effect of adjusting the formulation composition within a certain range on the antifoaming performance is relatively stable, and the product has good reliability.

[0189] The foam suppression performance of comparative examples 1-2 is significantly lower than that of the embodiments, with comparative example 1 being 68.41% and comparative example 2 being 71.36%, and the foam suppression performance being significantly lower than that of the embodiments; comparative example 3 being 95.15%, which is relatively high but still lower than most of the embodiments; this clearly shows that the foam suppressant of the present invention has a significant advantage in foam suppression ability over the comparative example samples.

[0190] By observing the types of formulas 1-1 to 1-8, formulas 2-1 to 2-8 and the antifoaming performance data of the silicone oil concentrate compositions in different embodiments, it is found that when the chain length and structure of the silicone oil concentrate composition change, the antifoaming performance shows a certain trend of change. For example, in formula 1, when the m value is small and the n value is within a certain range, the antifoaming performance is high in embodiments 1 and 2; and in formula 2, similar structure embodiments 9 and 10 also show high antifoaming performance, indicating that within a certain range of chain length ratios, the silicone oil concentrate composition is more conducive to exerting an antifoaming effect, and different chain lengths and structures have an impact on the surface tension of the system, the interfacial properties, and the synergistic effect with other components.

[0191] Comparing Comparative Example 1 using hydrophilic fumed silica or nano-silica and the examples of the present invention, the hydrophilic filler leads to a significant decrease in the antifoaming performance, indicating that hydrophobic treatment is crucial to improving the antifoaming performance; in the examples, when the filler ratio is in the range of 5-20wt%, although the overall data show that a good antifoaming effect can be achieved within this range, it can still be observed that the antifoaming performance fluctuates to a certain extent with the change in the filler ratio, indicating that the degree and ratio of the hydrophobic treatment of the filler also have an impact on the antifoaming performance.

[0192] 3.2 Analysis of storage stability evaluation results

[0193] The storage stability evaluation results are represented by symbols. In the examples, [◎] indicates that the storage stability is excellent, such as Examples 1, 2, 5, 9, 13, 14, 15, 16, etc., [○] indicates that no phase separation occurs within 3 months, but a certain proportion of the phase separation gradually occurs after 3 months, such as Examples 3, 4, 6, 7, 10, 12, etc., showing a polarized state as a whole, with good stability being the main case. In the comparative examples, [Χ] indicates that phase separation occurs more frequently within 3 months, such as Comparative Examples 1 and 2, and only Comparative Example 3 is [◎].

[0194] Most of the examples of the novel silicone antifoaming agent of the present invention have good performance in storage stability, some have excellent stability within 3 months and have a long-term stability trend, and a few may have phase separation after 3 months. Among the comparative examples, except for comparative example 3, the other comparative examples have stability problems in a short period of time, indicating that the antifoaming agent formula of the present invention has obvious advantages in storage stability, and reasonable raw material selection and process design are helpful to maintain the stability of the product.

[0195] 3.3 Analysis of smearability evaluation results

[0196] In the evaluation of spreadability, the various defect indicators of brush marks, orange peel, sagging, shrinkage cavities, and bubbles in Examples 1-16 are mostly "none", and the overall spreadability is good or relatively good. In the comparative examples, comparative examples 1 and 2 have serious defects in brush marks, orange peel, sagging, and shrinkage cavities, and comparative example 3 has only slight defects in brush marks, orange peel, and bubbles. The data distribution shows that the embodiments and comparative examples have obvious differences in spreadability.

[0197] As a coating additive, the novel siloxane foam suppressor of the present invention has excellent performance in terms of coating properties and basically does not produce defects that affect the coating quality. This is due to the synergistic effect of various components and reasonable processes, which ensure the good performance of the coating during coating. The comparative examples have more problems during the coating process due to different components or processes, which further reflects the advantages of the foam suppressor of the present invention in practical applications. It not only has strong foam suppression ability, but also can ensure the construction quality of the coating.

[0198] Comprehensive experimental results show that the new silicone foam suppressor of the present invention shows significant advantages in many aspects. In the evaluation of foam suppression ability, the foam suppression performance f values ​​of Examples 1-16 are mostly between 90% and 97%, with an average of 93.65%, and the hydrophobic treatment of the silicone oil concentrate composition and filler with a specific chain length ratio has a significant effect on the foam suppression performance, while the comparative examples are far less than the examples; in terms of storage stability, most of the examples perform well, some have excellent stability and a long-term stable trend, while the comparative examples mostly have phase separation problems in the short term; in the evaluation of spreadability, the examples are basically defect-free, and the spreadability is good or better, but the comparative examples have many serious defects. Overall, it shows that the foam suppressor has outstanding advantages in foam suppression, storage stability and spreadability, the synergistic effect of each component is good, the product performance is reliable, it has strong practicality and market competitiveness, and can effectively solve the foam problem of oily systems, especially suitable for high-viscosity oily systems.

Claims

1. A novel silicone foam suppressor, characterized in that: include: 2-10 parts of filler, 40-70 parts of silicone oil concentrate composition, 40-70 parts of high viscosity polydimethylsiloxane and 100-150 parts of fatty alcohol and propylene oxide polymer; The filler is a hydrophobically treated filler.

2. A novel silicone foam suppressor according to claim 1, characterized in that: The silicone oil concentrated composition comprises two silicone oil concentrated compositions, and the structure thereof is Formula 1: ； Formula 2: ； In the construction formula: R1 is a methyl group, R2 is a hydrogen atom, m is 0 to 50, n is 1 to 150, and the structure includes a variety of different chain lengths.

3. A novel silicone foam suppressor according to claim 2, characterized in that: The silicone oil concentrated composition is formula 1, and the preparation method is: S11 Solution preparation: In a container, add octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane considering the ratio of m to n, and add tetramethyldisiloxane according to the chain length; S12 catalyst addition: add 1-5% of the total mass of concentrated sulfuric acid as a catalyst, condense and reflux under nitrogen environment and heat and stir, the reaction temperature is controlled at 50-70°C, and the polymerization reaction lasts for 4-7 hours; S13 cooling and neutralization: adding solid sodium carbonate for neutralization to terminate the reaction, stirring until the pH value reaches neutral, and cooling naturally to room temperature; S14 Filtration and distillation: Filter the neutralized solid matter, and distill under reduced pressure at 70-90° C. for 3-5 hours to evaporate the low-boiling point substances to obtain a transparent liquid product, a silicone oil concentrated composition of Formula 1.

4. A novel silicone foam suppressor according to claim 2, characterized in that: The silicone oil concentrated composition is formulated as follows: S21 solution preparation: In a container, add octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane considering the ratio of m to n, and add hexamethyldisiloxane according to the chain length; S22 catalyst addition: add 1-5% of the total mass of concentrated sulfuric acid as a catalyst, condense and reflux under nitrogen environment and heat and stir, the reaction temperature is controlled at 50-70°C, and the polymerization reaction lasts for 4-7 hours; S23 cooling and neutralization: adding solid sodium carbonate for neutralization to terminate the reaction, stirring until the pH value reaches neutral, and naturally cooling to room temperature; S24 Filtration and distillation: Filter the neutralized solid matter, and distill under reduced pressure at 70-90° C. for 3-5 hours to evaporate the low-boiling point substances to obtain a transparent liquid product, a silicone oil concentrated composition of Formula 2.

5. A novel silicone foam suppressor according to claim 1 or 2, characterized in that: The silicone oil concentrated composition has different chain lengths. In each structural formula of Formula 1 and Formula 2, there are 8 siloxanes based on the ratio of m:n, and a total of 16 siloxanes, thereby obtaining 16 silicone oil concentrated compositions.

6. A novel silicone foam suppressor according to claim 1, characterized in that: The hydrophobic filler is hydrophobic treated fumed silica or nano-silicon dioxide with a specific surface area of ​​70-150m 2 / g, and the proportion in the novel silicone antifoam component is maintained at 5-20wt%.

7. A novel silicone foam suppressor according to claim 1, characterized in that: The hydrophobic treatment method is: under the action of the prepared silicone oil composition, heating the fumed silica or nano-silicon dioxide to 100 to 300° C. for 2-5 hours to make it hydrophobic, and the ratio of the silicone oil composition to the fumed silica or nano-silicon dioxide is 1:5-20.

8. A novel silicone foam suppressor according to claim 1, characterized in that: The preparation method of the hydrophobically treated filler is: a. Mixing the filler with the silicone oil concentrated composition: adding the hydrophobized fumed silica or nano-silicon dioxide to the prepared silicone oil concentrated composition in a ratio of 1:8-70, and mixing and stirring; b. Reaction and heating: heating the mixture to 150-180° C. and reacting for 6-8 hours under stirring to obtain a hydrophobic treated filler having a silicone oil concentrated composition on its surface; c. Treatment after the reaction is completed: the hydrophobic treated filler containing the silicone oil concentrated composition on the surface is directly stored and kept without centrifugation, the unused filler is used after centrifugal separation and drying, and the unreacted silicone oil concentrated composition is collected and recycled.

9. A production process of the novel silicone foam suppressor according to claim 1, characterized in that: The specific steps are: 1-5 parts of a hydrophobically treated filler are mixed with 40-70 parts of a silicone oil concentrate composition and stirred, 40-70 parts of a high-viscosity polydimethylsiloxane and 100-150 parts of a nonionic surfactant are further added, and stirred at a high speed, oleic acid is added to the stirred basic formula of the foam suppressor, and heated to react, thereby obtaining a novel silicone foam suppressor.

10. The production process of a novel silicone foam suppressant according to claim 8, characterized in that: The nonionic surfactant is a polymer of fatty alcohol and propylene oxide, has a neutral pH value, and a hydroxyl value less than or equal to 35 mgKOH / g; The amount of oleic acid used accounts for 0.5-3.0% of the total mass of the antifoaming agent.

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