High temperature durable silicone defoaming composition and method of making same

Abstract

The application provides a high-temperature durable organic silicon defoaming composition, which comprises alkyl polysiloxane, phenylsiloxane, fluorine-containing siloxane, hydrophobic modified silicon dioxide, an antioxidant and a dispersant; various groups, such as alkyl, benzene rings and fluorine-containing groups, are introduced into the side chains of the polysiloxane; in the defoaming composition, the introduction of the phenylsiloxane makes the molecular structure more stable, the defoaming composition can keep low volatility and excellent chemical stability under high-temperature conditions; the fluorine-containing groups further enhance the thermal stability of the polysiloxane at the molecular level, reduce the surface energy and increase the adhesion capacity of the defoaming agent at the gas-liquid interface. The optimized combination of the modified groups, the dispersant and the antioxidant endows the defoaming agent with strong oxidation resistance and chemical resistance, and the defoaming agent can also work stably in a production environment with strong oxygen, acidity or alkalinity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fine chemicals, and particularly relates to a high-temperature durable organosilicon defoaming composition and a preparation method thereof. BACKGROUND

[0002] In the industrial fields of petroleum chemical industry, textile dyeing and finishing, metal working fluid, distillation and purification, the production process is usually accompanied by the generation of foam, especially under high temperature and high pressure conditions. If these foams cannot be effectively controlled, not only the efficiency of the equipment will be reduced, but also the equipment and products may be damaged, and even safety hazards may be caused. Taking petroleum refining and chemical production as an example, high temperature and high pressure conditions are often required in the production process. If the foam is not eliminated in time, it will cause the production line to stop, the flow to be blocked or the pipeline to be blocked, which seriously affects the production progress and equipment safety.

[0003] The conventional defoamers on the market are mostly dimethyl polysiloxane type, mineral oil type, vegetable oil type or polyether type. Although they can effectively defoam at room temperature, they often fail, decompose and have other problems under high temperature conditions, resulting in the inability to continuously and effectively defoam. The polyether type defoamer is prone to decomposition or oxidation reaction at a higher temperature, and the defoaming effect is greatly reduced. The dispersibility of the mineral oil type defoamer is poor, and it is difficult to stably adhere to the gas-liquid interface. The defoaming efficiency of the vegetable oil type defoamer is reduced at high temperature, and the foam suppression time is short. The traditional organosilicon defoamer also has the problems of molecular chain breaking and defoaming structure damage under high temperature conditions, and it is difficult to meet the long-term foam suppression demand. Therefore, it is an urgent need in actual production to develop an organosilicon defoamer that can work continuously under high temperature conditions. SUMMARY

[0004] The embodiments of the present application provide a high-temperature durable organosilicon defoaming composition, a preparation method thereof and a defoaming preparation to solve the problems in the related art, and the technical solutions are as follows:

[0005] In the first aspect, the embodiments of the present application provide a high-temperature durable organosilicon defoaming composition, which comprises the following components in parts by weight:

[0006] Alkyl polysiloxane: 50.0-60.0 parts;

[0007] Phenylsiloxane: 10.0-15.0 parts;

[0008] Fluorine-containing polysiloxane: 10.0-15.0 parts;

[0009] Hydrophobic modified silicon dioxide: 2.0-5.0 parts;

[0010] Antioxidant: 0.1-1.0 parts;

[0011] Dispersant: 3.0-8.0 parts.

[0012] In one embodiment, the alkyl polysiloxane has the structure of Formula I:

[0013] (Formula I);

[0014] wherein R1 is a C2-C8 alkyl group; m = 60-500, and m is an integer.

[0015] In one embodiment, the phenyl siloxane is a methyl phenyl polysiloxane having the structure of Formula II:

[0016] (Formula II);

[0017] x = 10-200, and x is an integer.

[0018] In one embodiment, the fluorosilicone has the structure of Formula III:

[0019] (Formula III);

[0020] wherein n = 3-10, and n is an integer; y = 10-200, and y is an integer.

[0021] In one embodiment, the hydrophobically modified silica is a fumed silica or a precipitated silica modified with a modifier; the modifier is one or a combination of polydimethylsiloxane, polydimethylsilazane, long chain alkyl silane, phenyl silane, or epoxy silane.

[0022] In one embodiment, the dispersant is a polyether, alkane, or polyether alkane co-modified polysiloxane.

[0023] In one embodiment, the dispersant has the structure of Formula IV:

[0024] (Formula IV);

[0025] wherein R2 is an ethoxylated and / or propoxylated polyether group having the structure of -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e = 0-10, f = 5-30, g = 3-5, and e, f, g are integers; R3 is a C1-C8 alkyl group; p = 0-100, q = 0-100, and p, q are integers, and p and q are not both 0.

[0026] In one embodiment, the antioxidant is a German BASF antioxidant.

[0027] In an embodiment, the antioxidant is one or a combination of two or more of Organo 1010, 1098, 1035, 1135, 1425, 1076, 245.

[0028] In a second aspect, the embodiments of the present application provide a preparation method of a high-temperature durable organosilicon defoaming composition, comprising the following steps:

[0029] S1: mixing and stirring alkyl polysiloxane, phenylsiloxane and fluorine-containing polysiloxane, and heating to 50-100℃ to obtain a first mixture;

[0030] S2: adding hydrophobic modified silica and an antioxidant to the first mixture, and stirring and mixing and dispersing at 50-100℃ to obtain a second mixture;

[0031] S3: adding a dispersant to the second mixture, and stirring and dispersing to obtain the high-temperature durable organosilicon defoaming composition.

[0032] In an embodiment, in steps S1-S3, the stirring speed is 1000-2500 rpm;

[0033] In step S1, the stirring time is 0.5-2h; in step S2, the stirring time is 0.2-1h; and in step S3, the stirring time is 0.2-1h.

[0034] The advantages or beneficial effects of the above technical solution at least include:

[0035] The high-temperature durable organosilicon defoaming composition of the present application comprises a combination of various modified polysiloxanes, and various groups such as alkyl, benzene ring and fluorine-containing groups are introduced into the side chain of polysiloxane. The benzene ring and fluorine-containing groups are not easy to decompose at high temperature, and have high resistance to chemical reactions, so that the defoaming agent is not easy to decompose or volatilize under high temperature conditions. Therefore, in the defoaming composition of the present application, the introduction of phenylsiloxane makes the molecular structure more stable, and can maintain low volatility and excellent chemical stability under high temperature conditions; the fluorine-containing group further enhances the thermal stability of polysiloxane at the molecular level, reduces the surface energy, and increases the adhesion ability of the defoaming agent at the gas-liquid interface. The optimized combination of modified groups, dispersants and antioxidants gives the defoaming agent strong antioxidant properties and chemical resistance, and it can also work stably in production environments with high oxygen, acidity or alkalinity.

[0036] The above summary is for the purpose of description only and is not intended to limit in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features will become apparent to those skilled in the art from the following detailed description. Detailed Implementation

[0037] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the following description is considered to be exemplary in nature and not restrictive.

[0038] In various high-temperature production scenarios such as petrochemicals, textile dyeing and finishing, pulp and paper making, and metal cleaning, defoaming agents not only need to have good defoaming effects but also need to meet the requirements of high-temperature environments. While dimethyl polysiloxane-based, mineral oil-based, vegetable oil-based, or polyether-based defoamers are effective at room temperature, they often face problems such as ineffectiveness and decomposition at high temperatures, resulting in a lack of sustained and effective defoaming. Therefore, this application provides a high-temperature durable organosilicon defoaming composition and its preparation method.

[0039] A high-temperature durable silicone defoaming composition comprising the following components in parts by weight:

[0040] Alkyl polysiloxane: 50.0-60.0 parts;

[0041] Phenylsiloxane: 10.0-15.0 parts;

[0042] Fluorinated polysiloxane: 10.0-15.0 parts;

[0043] Hydrophobically modified silica: 2.0-5.0 parts;

[0044] Antioxidant: 0.1-1.0 parts;

[0045] Dispersant: 3.0-8.0 parts.

[0046] Modified polysiloxane is used as the main material, and its stability under high-temperature conditions is improved by introducing phenyl and fluorine-containing groups with high-temperature resistance. Special modified fumed silica is added as a synergist and structural stabilizer, and a high-performance antioxidant is added to further improve the thermal stability and durability of the defoamer. By rationally controlling the proportions of modified polysiloxane, phenyl and fluorine-containing groups, modified fumed silica, and antioxidants, the defoamer can achieve optimal defoaming effect and durability at higher temperatures. In addition, an appropriate amount of dispersant is added to the formulation to ensure the dispersibility and adhesion of the defoamer in high-temperature environments, thereby achieving long-lasting defoaming and foam-suppressing performance.

[0047] In one embodiment, the structure of the alkyl polysiloxane is shown in Formula I:

[0048] (Formula I);

[0049] wherein R1 is C2-C8 alkyl; m = 60-500, and m is an integer.

[0050] In the present embodiment, R1 is C2-C8 alkyl; as a preferred embodiment, R1 can be ethyl, n-propyl, iso-propyl, butyl, hexyl, octyl. m = 60-500, and m is an integer, m can be any integer between 60-500.

[0051] In one embodiment, the phenylsiloxane is a methylphenylpolysiloxane, the structure of which is shown in Formula II:

[0052] (Formula II);

[0053] x = 10-200, and x is an integer.

[0054] In the present embodiment, the benzene ring is a strong carbon ring structure, which has good high-temperature resistance. Therefore, the introduction of the phenyl group in the side chain of polysiloxane makes the polysiloxane molecular structure more stable, and can maintain low volatility and excellent chemical stability under high-temperature conditions, thereby improving the high-temperature resistance of the phenylsiloxane. In the present embodiment, x can be any integer between 10-200. Compared with ordinary polydimethylsiloxane groups, the phenyl group is not easy to decompose at high temperatures, and has high resistance to chemical reactions, and thus is suitable for use in high-temperature industrial environments.

[0055] In one embodiment, the fluorine-containing polysiloxane has the structure shown in Formula III:

[0056] (Formula III);

[0057] wherein n = 3-10, and n is an integer; y = 10-200, and y is an integer.

[0058] The fluorine-containing group has strong chemical inertness, can reduce surface energy, increase the spreading performance of the defoamer, and help to quickly distribute on the liquid surface, while being resistant to oxidation and other chemical corrosion. The fluorine-containing group further enhances the thermal stability of the polysiloxane at the molecular level, reduces the surface energy, and increases the adhesion of the defoamer to the gas-liquid interface. Compared with ordinary polydimethylsiloxane groups, the fluorine-containing group is not easy to decompose at high temperatures, and has high resistance to chemical reactions, and thus is suitable for use in high-temperature industrial environments. As a linking group, the length of -CH2- is not too short, and thus n is selected to be any integer between 3-10. In the present embodiment, y can be any integer between 10-200.

[0059] In one embodiment, the hydrophobically modified silica is a fumed silica or a precipitated silica modified by a modifier; the modifier is one or a combination of polydimethylsiloxane, polydimethylsilazane, long chain alkyl silane, phenyl silane, or epoxy silane. Preferably, the modifier is one or a combination of hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, hexamethyldisilazane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octamethyltriamethoxysilane, octamethyltriamethoxysilane, phenyltrimethoxysilane, or phenyltriethoxysilane. Preferably, the hydrophobic fumed silica is at least one of Evonik-R974, Evonik-R972, Evonik-R816, Evonik-R812S, Evonik-R812, Evonik-R202, Evonik-R106, Evonik-R104, Cabot TS-610, Cabot TS-530, Japan DeShan DM-30, Japan DeShan DM-20S, Germany Wacker-H20, or Germany Wacker-H30.

[0060] The hydrophobically modified silica as a structure aid can improve the dispersibility and adhesion of the defoamer. The silica particles are treated by hydrophobicity, which can be stable at high temperature, improve the adhesion of the defoamer, and further strengthen the defoaming performance.

[0061] In the present embodiment, the method for modifying the silica is:

[0062] The fumed silica or the precipitated silica is reacted with the modifier under the catalyst to modify the silica. The catalyst is a silane coupling agent, such as KH-602, APMDS, etc. The reaction is carried out at 50-80°C, and the reaction time is 2-12h.

[0063] In one embodiment, the dispersant is a polyether, alkane, or polyether-alkane co-modified polysiloxane. The dispersant is added in the formula to ensure that the defoamer can be uniformly distributed at the gas-liquid interface and will not volatilize or condense rapidly at high temperature.

[0064] In one embodiment, the dispersant has the structure as shown in Formula IV:

[0065] (Formula IV);

[0066] wherein R2 is an ethoxylated and / or propoxylated polyether group, and has the structure of -(CH2) g (OCH2CH2) e (OCH2CH2CH2) fOH, e = 0-10, f = 5-30, g = 3-5, and e, f, g are integers; R3 is a C1-C8 alkyl group; p = 0-100, q = 0-100, and p, q are integers, and p and q are not simultaneously 0.

[0067] In an embodiment, the antioxidant is a BASF antioxidant. The addition of high performance antioxidant further improves the stability of the defoamer active ingredient in high temperature environment, reduces and delays the oxidation and chain breaking process of the active ingredient molecules, and greatly improves the durability and effectiveness of the defoaming performance in high temperature environment.

[0068] In an embodiment, the antioxidant is one or a combination of more than two of organox 1010, 1098, 1035, 1135, 1425, 1076, and 245.

[0069] The application also provides a preparation method of a high-temperature durable organosilicon defoaming composition, comprising the following steps:

[0070] S1: mixing and stirring alkyl polysiloxane, phenylsiloxane, and fluorosilicone, and heating to 50-100°C to obtain a first mixture;

[0071] S2: adding hydrophobic modified silica and an antioxidant to the first mixture, and stirring and mixing and dispersing at 50-100°C to obtain a second mixture;

[0072] S3: adding a dispersant to the second mixture, and stirring and dispersing to obtain the high-temperature durable organosilicon defoaming composition.

[0073] In an embodiment, in steps S1-S3, the stirring speed is 1000-2500 rpm.

[0074] In step S1, the stirring time is 0.5-2 h; in step S2, the stirring time is 0.2-1 h; and in step S3, the stirring time is 0.2-1 h.

[0075] The following is further illustrated with specific examples.

[0076] Example 1

[0077] A high-temperature durable organosilicon defoaming composition comprises the following components in parts by weight:

[0078] Alkyl polysiloxane 55 parts; phenylsiloxane 13 parts; fluorosilicone 13 parts; hydrophobic modified silica 3.5 parts; antioxidant 0.5 parts; dispersant 5 parts;

[0079] The alkyl polysiloxane is shown in formula I, wherein R1 is n-butyl; m is 80.

[0080] Phenylsiloxane is shown as formula II, wherein x is 50;

[0081] Fluorine-containing polysiloxane is shown as formula III, wherein n is 3, y is 50;

[0082] Hydrophobic modified silica is prepared by reacting fumed silica with decamethyltetrasiloxane in the presence of silane coupling agent KH-602 at a mass ratio of 10:3:2 at 70℃ for 10h;

[0083] Dispersant is shown as formula IV, wherein R2 is ethoxylated and / or propoxylated polyether group, structure is -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e=5, f=10, g=4; R3 is ethyl; p=20, q=30.

[0084] Antioxidant is a combination of Organo 1010 and 1135 at a mass ratio of 1:1;

[0085] Prepared by the following method:

[0086] S1: Mix alkyl polysiloxane, phenylsiloxane, fluorine-containing polysiloxane and stir at a speed of 2000rpm, heat to 75℃, stir for 1h to obtain a first mixture;

[0087] S2: Add hydrophobic modified silica and antioxidant to the first mixture, stir at a speed of 2000rpm at 75℃ for 0.5h after mixing and dispersing, to obtain a second mixture;

[0088] S3: Add dispersant to the second mixture, stir at a speed of 2000rpm for 1h after dispersing, to obtain a high-temperature durable silicone defoaming composition.

[0089] Example 2

[0090] A high-temperature durable silicone defoaming composition, comprising the following components by weight parts:

[0091] Alkyl polysiloxane 50 parts; phenylsiloxane 15 parts; fluorine-containing polysiloxane 10 parts; hydrophobic modified silica 5 parts; antioxidant 0.1 parts; dispersant 8 parts;

[0092] Alkyl polysiloxane is shown as formula I, wherein R1 is ethyl; m is 200;

[0093] Phenylsiloxane is shown as formula II, wherein x is 10;

[0094] fluorosilicone is shown as formula III, wherein n is 5, y is 100;

[0095] The hydrophobic modified silica is prepared by reacting fumed silica with hexadecyltrimethoxysilane in the presence of silane coupling agent APMDS at a mass ratio of 10:4:1.5 at 50°C for 12h;

[0096] The dispersant is shown as formula IV, wherein R2 is an ethoxylated and / or propoxylated polyether group, and the structure is -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e=10, f=20, g=3; p=50, q=0.

[0097] The antioxidant is OrganoX 1076;

[0098] Prepared by the following method:

[0099] S1: Mix the alkyl polysiloxane, phenyl siloxane, and fluorosilicone, and stir at a speed of 1500rpm, and heat to 50°C, and stir for 2h to obtain a first mixture;

[0100] S2: Add the hydrophobic modified silica and antioxidant to the first mixture, and stir at a speed of 1500rpm at 50°C for 1h after mixing and dispersing to obtain a second mixture;

[0101] S3: Add the dispersant to the second mixture, and stir at a speed of 1500rpm for 0.2h after dispersing to obtain the high-temperature durable silicone defoaming composition.

[0102] Example 3

[0103] A high-temperature durable silicone defoaming composition, comprising the following components in parts by weight:

[0104] Alkyl polysiloxane 60 parts; phenyl siloxane 10 parts; fluorosilicone 15 parts; hydrophobic modified silica 2 parts; antioxidant 1 part; dispersant 3 parts;

[0105] The alkyl polysiloxane is shown as formula I, wherein R1 is n-octyl; m is 60;

[0106] The phenyl siloxane is shown as formula II, wherein x is 10;

[0107] The fluorosilicone is shown as formula III, wherein n is 10, y is 100;

[0108] The hydrophobic modified silica is prepared by reacting fumed silica with phenyltrimethoxysilane in the presence of silane coupling agent KH-602 at a mass ratio of 10:2:1 at 80°C for 2h;

[0109] The dispersant is shown in Formula IV, wherein R2 is an ethoxylated and / or propoxylated polyether group, and the structure is -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e=10, f=0, g=5; R3 is n-hexyl; p=10, q=50.

[0110] The antioxidant is OrganoX 1010;

[0111] Prepared by the following method:

[0112] S1: The alkyl polysiloxane, phenyl siloxane, fluorine-containing polysiloxane are mixed and stirred at a speed of 1000 rpm, and the temperature is raised to 85°C, and stirred for 1h to obtain a first mixture;

[0113] S2: The hydrophobic modified silica and antioxidant are added to the first mixture, and after mixing and dispersing at 85°C and a stirring speed of 1000 rpm for 0.5h, a second mixture is obtained;

[0114] S3: The dispersant is added to the second mixture, and after dispersing at a stirring speed of 1000 rpm for 0.5h, a high-temperature durable silicone defoaming composition is obtained.

[0115] Comparative Example 1 (without phenyl silane, heat resistance decreased)

[0116] Comparative Example 1 and Example 1 differ in that a defoaming composition includes the following components by weight:

[0117] 68 parts of alkyl polysiloxane; 13 parts of fluorine-containing polysiloxane; 3.5 parts of hydrophobic modified silica; 0.5 parts of antioxidant; 5 parts of dispersant; and the other substances, composition and preparation method are the same as those of Example 1.

[0118] Comparative Example 2 (without fluorine-containing silane, defoaming performance decreased)

[0119] Comparative Example 2 and Example 1 differ in that a defoaming composition includes the following components by weight:

[0120] 68 parts of alkyl polysiloxane; 13 parts of fluorine-containing polysiloxane; 3.5 parts of hydrophobic modified silica; 0.5 parts of antioxidant; 5 parts of dispersant; and the other substances, composition and preparation method are the same as those of Example 1.

[0121] Comparative Example 3 (silica not modified, defoaming performance decreased)

[0122] Comparative Example 3 differs from Example 1 in that a defoaming composition includes the following components by weight parts:

[0123] alkyl polysiloxane 55 parts; phenyl siloxane 13 parts; fluorine-containing polysiloxane 13 parts; fumed silica 3.5 parts; antioxidant 0.5 parts; dispersant 5 parts; other substances are the same as in Example 1 in composition and preparation method.

[0124] Comparative Example 4 (no dispersant, defoaming performance decreased)

[0125] Comparative Example 4 differs from Example 1 in that a defoaming composition includes the following components by weight parts:

[0126] alkyl polysiloxane 55 parts; phenyl siloxane 13 parts; fluorine-containing polysiloxane 13 parts; hydrophobic modified silica 3.5 parts; antioxidant 0.5 parts; other substances are the same as in Example 1 in composition and preparation method.

[0127] Comparative Example 5 (no fluorine-containing silane and phenyl silane, defoaming performance decreased)

[0128] Comparative Example 5 differs from Example 1 in that a high-temperature durable silicone defoaming composition includes the following components by weight parts:

[0129] alkyl polysiloxane 81 parts; hydrophobic modified silica 3.5 parts; antioxidant 0.5 parts; dispersant 5 parts; other substances are the same as in Example 1 in composition and preparation method.

[0130] Comparative Example 6 (no antioxidant, defoaming performance decreased)

[0131] Comparative Example 6 differs from Example 1 in that a defoaming composition includes the following components by weight parts:

[0132] alkyl polysiloxane 55 parts; phenyl siloxane 13 parts; fluorine-containing polysiloxane 13 parts; hydrophobic modified silica 3.5 parts; dispersant 5 parts; other substances are the same as in Example 1 in composition and preparation method.

[0133] Comparative Example 7 (high content of alkyl polysiloxane)

[0134] Comparative Example 7 differs from Example 1 in that a defoaming composition includes the following components by weight parts:

[0135] Alkyl polysiloxane 90 parts; phenylsiloxane 13 parts; fluorine-containing polysiloxane 13 parts; hydrophobic modified silica 3.5 parts; antioxidant 0.5 parts; dispersant 5 parts; other substances, composition and preparation method are the same as example 1.

[0136] Test example:

[0137] Test method:

[0138] (1) The composition of example 1 and comparative examples 1-7 was placed in an oven at 200℃ for 1h, and the change in properties before and after was compared, and the results are shown in Table 1.

[0139] Table 1

[0140]

[0141] From the results in Table 1, it can be seen that the defoaming agent of example 1 of the present application has certain high temperature resistance, while the defoaming agents of comparative examples 1-7 exhibit a certain degree of change in properties at high temperature of 200℃; the defoaming agents of comparative examples 1-7 have obvious changes in viscosity after high temperature treatment, indicating poor thermal stability. The viscosity of the defoaming composition of example 1 of the present application is basically unchanged, showing good thermal stability.

[0142] (2) The reaction liquid in the petroleum refining process was used as the test medium, and the test sample foam was prepared to the same height by air blowing; the defoaming agent was added, and the time for the foam to reach different volumes was recorded. The longer the time required, the worse the foam suppression performance of the sample.

[0143] Test conditions: test temperature 200℃; amount of reaction liquid in petroleum refining process: 300ml; sample addition amount of example 1-3 and comparative examples 1-7: 30μL; test flow rate: 5L / min. The results are shown in Table 2.

[0144] (3) The test temperature was changed to 100℃, and the time for the foam to reach less than 50ml from the preparation height was determined, and the results are shown in Table 3.

[0145] Table 2 test result table

[0146]

[0147] Table 3 test result table

[0148]

[0149] As can be seen from Table 2, the defoaming agents of Examples 1-3 can eliminate the foam generated by the reaction liquid in the petroleum refining process from 1000 ml to less than 100 ml at 200℃ in about 5 min, while the same effect of Comparative Examples 1-7 takes a longer time, and the foam reaches less than 100 ml, and the time used is longer than the examples, indicating that the defoaming performance of the defoaming agent is not as good as the examples. Comparative Example 1 and Comparative Example 2 do not contain phenylsiloxane and siloxane containing fluorine group respectively, and Comparative Example 5 does not contain both of the above two siloxanes, and the time required for defoaming is greatly prolonged from 5 min to more than 8 min and a half, especially, as the defoaming proceeds, the time required for the foam volume to decrease by 150 ml is also prolonged, because at 200℃ high temperature, the defoaming performance of the defoaming agent is not greatly affected by high temperature at the beginning, and as the time at high temperature increases, the activity of the defoaming agent decreases due to high temperature, and thus the defoaming performance decreases significantly.

[0150] Comparative Example 3 shows that the hydrophobic modification of silica as a structure aid can improve the dispersibility and adhesion of the defoaming agent, and enable it to exist stably at high temperature, improve the adhesion of the defoaming agent, and thus strengthen the defoaming performance. Comparative Example 4 shows that the dispersant ensures that the defoaming agent can form uniform distribution at the gas-liquid interface, and will not volatilize or condense rapidly at high temperature, which also helps the defoaming agent to play a defoaming role. Comparative Example 6 shows that the oxidizing agent helps to stabilize in a high temperature environment, reduces and delays the oxidation and chain scission process of the active ingredient molecules, and greatly improves the durability and effectiveness of the defoaming performance in a high temperature environment. Comparative Example 7 shows that the defoaming agent of the present application can ensure the stability of the defoaming agent in a high temperature environment.

[0151] As can be seen from Table 3, the defoaming agent of Example 1 has little change in defoaming time at 200℃ and 100℃, showing excellent high-temperature defoaming effect; while the defoaming agents of Comparative Examples 1-7 have better defoaming effect at 100℃ than at 200℃, which shows that at high temperature, the stability of the defoaming agent decreases, resulting in a decrease in defoaming performance. The increase in temperature causes the defoaming performance of the defoaming agents of Comparative Examples 1-7 to decrease. This indirectly shows that the thermal stability of the defoaming agents of Comparative Examples 1-7 is not as good as that of the defoaming agents of the examples.

[0152] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Also, the specific features, structures, materials or characteristics described can be combined in an appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0153] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0154] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A high-temperature durable silicone defoaming composition, characterized in that, Including by weight The following components: Alkyl polysiloxane: 50.0-60.0 parts; Phenylsiloxane: 10.0-15.0 parts; Fluorinated polysiloxane: 10.0-15.0 parts; Hydrophobically modified silica: 2.0-5.0 parts; Antioxidant: 0.1-1.0 parts; Dispersant: 3.0-8.0 parts; The structure of the alkyl polysiloxane is shown in Formula I: (Equation I); Where R1 is a C2-C8 alkyl group; m = 60-500, and m is an integer; The phenylsiloxane is a methylphenylpolysiloxane, with the structure shown in Formula II: (Formula II); x = 10 - 200, where x is an integer; The structure of the fluorinated polysiloxane is shown in Formula III: (Formula III); Where n = 3 - 10, and n is an integer; y = 10 - 200, and y is an integer; The hydrophobic modified silica is fumed silica or precipitated silica modified by a modifier; the modifier is one or more of polydimethylsiloxane, polydimethylsilazane, long-chain alkylsilane, phenylsilane, or epoxysilane. The structure of the dispersant is shown in Formula IV: (Formula IV); R2 is an ethoxylated and / or propoxylated polyether group with the structure -(CH2). g (OCH2CH2) e (OCH2CH2CH2) f OH, e=0-10, f=5-30, g=3-5, and e, f, and g are integers; R3 is a C1-C8 alkyl group; p=0-100, q=0-100, and p and q are integers, and p and q are not both 0.

2. The high-temperature durable silicone defoaming composition according to claim 1, characterized in that, The dispersant is a polyether, an alkane, or a polyether-alkane co-modified polysiloxane.

3. The high-temperature durable silicone defoaming composition according to claim 1, characterized in that, The antioxidant is a German BASF series antioxidant.

4. The high-temperature durable silicone defoaming composition according to claim 1, characterized in that, The antioxidant is one or a combination of two or more of rganox 1010, 1098, 1035, 1135, 1425, 1076, and 245.

5. A method for preparing a high-temperature durable organosilicon defoaming composition according to any one of claims 1-4, characterized in that, Includes the following steps: S1: Mix and stir alkyl polysiloxane, phenyl siloxane, and fluorinated polysiloxane, and heat to 50-100℃ to obtain the first mixture; S2: Add hydrophobically modified silica and antioxidant to the first mixture, and stir and disperse at 50-100℃ to obtain the second mixture; S3: Add a dispersant to the second mixture, stir and disperse to obtain a high-temperature durable silicone defoaming composition.

6. The method for preparing an antifoaming composition as described in claim 5, characterized in that: In steps S1-S3, the stirring speed is 1000-2500 rpm; In step S1, the stirring time is 0.5-2 hours; in step S2, the stirring time is 0.2-1 hour; in step S3, the stirring time is 0.2-1 hour.

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