Quickly Dispersible Organosilicon Defoaming Composition and Its Preparation Method

Abstract

The present application provides a low-temperature rapid-dispersing silicone defoaming composition and its preparation method, which comprises a low-molecular-weight alkane-modified polysiloxane, a composite surfactant, hydrophobic particles and a polyether wetting aid. Using the low-molecular-weight alkane-modified polysiloxane as the base material ensures good fluidity and high dispersibility of the defoaming composition under low-temperature conditions; combined with a composite surfactant of non-ionic and anionic types, a polyether wetting aid, hydrophobic particles and a dispersant, it further enhances the dispersibility and fluidity of the defoaming composition in a low-temperature environment, reduces the surface tension of the foam; enables the defoaming composition to quickly diffuse at the gas-liquid interface, quickly reach the gas-liquid interface of the foam, and rapidly disintegrate the foam, ensuring that the defoaming agent still maintains a rapid defoaming effect in a low-temperature environment.

Description

Technical Field

[0001] This application belongs to the technical field of fine chemical industry, and particularly relates to a low-temperature rapid-dispersing silicone defoaming composition and a preparation method thereof. Background Art

[0002] In modern industrial production, the foam problem under low-temperature conditions is particularly prominent. Especially in processes such as the paper-making industry, food processing, and fermenter production, low-temperature foam brings a series of production problems. Taking paper-making as an example, a large amount of foam is generated in the pulp white water at a temperature of 5 - 10 °C. If the foam cannot be quickly eliminated, it will not only affect the product quality, but also hinder the smooth flow of the conveying pipeline and affect the normal operation of the equipment. At the same time, in food processing and fermentation processes, foam is also likely to cause hygiene and safety problems. The foam hinders the liquid flow, may lead to uneven product quality, increases the production control difficulty and production time cost.

[0003] Traditional silicone defoamers have good effects at normal temperature, but under low-temperature conditions, there will be problems with poor dispersibility, resulting in the defoamer being difficult to quickly reach the gas-liquid interface, and the defoaming effect will decline accordingly. The reason is that the low-temperature environment will limit the fluidity and molecular diffusion rate of the defoamer, making it difficult for the defoamer to be effectively distributed on the foam surface and unable to quickly play its role. Therefore, developing a silicone defoamer that can be quickly dispersed and highly defoamed under low-temperature conditions has become an urgent need in production. This can not only solve the foam problem in low-temperature processes, but also improve the overall production efficiency and product quality. Summary of the Invention

[0004] The embodiments of this application provide a low-temperature rapid-dispersing silicone defoaming composition and a preparation method thereof to solve the problems existing in the related technologies. The technical solutions are as follows:

[0005] In the first aspect, the embodiments of this application provide a low-temperature rapid-dispersing silicone defoaming composition, including the following components by weight:

[0006] Low molecular weight alkane-modified polysiloxane: 60 - 75 parts;

[0007] Compound surfactant: 10 - 20 parts;

[0008] Hydrophobic particles: 1 - 5 parts;

[0009] Polyether wetting aid: 5 - 10 parts.

[0010] In one embodiment, the low-temperature rapid-dispersing silicone defoaming composition further includes 1 - 3 parts of a dispersant and / or synergist by weight.

[0011] In one embodiment, the structure of the low molecular weight alkane-modified polysiloxane is shown in Formula I:

[0012] (Formula I);

[0013] wherein R1 is an alkyl group having 2 to 8 carbon atoms; m = 1 - 50, and m is an integer.

[0014] In one embodiment, the composite surfactant is a nonionic and anionic composite surfactant.

[0015] In one embodiment, the nonionic surfactant is one or a combination of two or more of ethoxylated and / or propoxylated fatty alcohols, ethoxylated and / or propoxylated glycerol ethers, alkyl polyethylene glycol ethers, polyethylene glycols, and polyvinyl alcohols;

[0016] The anionic surfactant is fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate and / or fatty alcohol polyoxyethylene / polyoxypropylene ether sulfonate.

[0017] In one embodiment, the hydrophobically modified silica is fumed silica or precipitated silica modified with a modifier; the modifier is one or a combination of two or more of polydimethylsiloxane, polydimethylsilazane, long-chain alkylsilane, or phenylsilane.

[0018] In one embodiment, the modifier is one or a combination of two or more of hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, hexamethyldisilazane, hexadecyltrimethoxy(triethoxy)silane, octamethyltrimethoxy(triethoxy)silane, or phenyltrimethoxy(triethoxy)silane.

[0019] In one embodiment, the polyether wetting aid is an organosilicon-modified polyether wetting agent; the structure of the organosilicon-modified polyether wetting agent is shown in Formula II:

[0020] (Formula II);

[0021] wherein R2 is an ethoxylated and / or propoxylated polyether group, and R3 and R4 are methyl, ethyl, ethoxylated and / or propoxylated polyether groups; the ethoxylated and / or propoxylated polyether group has a structure of -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e = 5 - 10, f = 0 - 30, g = 3 - 5, and e, f, and g are integers; k = 1 - 10, and k is an integer.

[0022] In one embodiment, the structures of the dispersant and the synergist are shown in Formula III:

[0023] (Formula III);

[0024] wherein R5 is a polyether or polyether ester, R6 is an alkyl or aryl group; p = 0 - 100, q = 0 - 100, and p and q are integers, where p and q are not both 0 at the same time.

[0025] In a second aspect, an embodiment of the present application provides a method for preparing a low-temperature rapid-dispersing silicone defoaming composition, comprising the following steps:

[0026] S1. Weigh a low-molecular-weight alkane-modified polysiloxane, a composite surfactant, hydrophobic particles, and a polyether wetting aid in proportion, and sequentially add them to a stirring container;

[0027] S2. Start the stirring device, and under the condition of low-speed stirring, gradually mix the components evenly;

[0028] S3. After mixing evenly, slowly add a dispersant and a synergist, continue stirring, and gradually increase the stirring speed to form a uniform and stable dispersion in the whole system;

[0029] S4. The whole stirring process needs to last for a certain time until the components of the defoaming composition are completely fused and there is no obvious stratification or particle precipitation, obtaining the low-temperature rapid-dispersing silicone defoaming composition.

[0030] The advantages or beneficial effects in the above technical solutions at least include:

[0031] A low-temperature rapid-dispersing silicone defoaming composition of the present application includes a low-molecular-weight alkane-modified polysiloxane, a composite surfactant, hydrophobic particles, and a polyether wetting aid. Using the low-molecular-weight alkane-modified polysiloxane as the base material ensures good fluidity and high dispersion ability of the defoaming composition under low-temperature conditions; the composite surfactant adopts non-ionic and anionic types, which not only enables the defoaming composition to still maintain excellent dispersibility and fluidity in a low-temperature environment, but also can quickly diffuse at the gas-liquid interface to form a stable interface, effectively inhibiting the re-generation of foam; and the polyether wetting aid further reduces the surface tension of the foam, enabling the defoaming agent to quickly reach the gas-liquid interface of the foam and rapidly disintegrate the foam, ensuring that the defoaming agent still maintains a rapid defoaming effect in a low-temperature environment. Modified fumed silica, as a synergist and a structure stabilizer, can improve the dispersibility and adhesion of the defoaming agent; by continuously optimizing the proportions of the low-molecular-weight polysiloxane, the composite surfactant, the hydrophobic particles, and the polyether wetting aid, the present application achieves rapid dispersion and high-efficiency defoaming in a low-temperature environment.

[0032] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present application will become readily apparent by reference to the following detailed description. Detailed Embodiments

[0033] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the following description is considered to be exemplary in nature and not restrictive.

[0034] The present application provides a low-temperature rapid-dispersing silicone defoaming composition, comprising the following components by weight:

[0035] Low-molecular-weight alkane-modified polysiloxane: 60 - 75 parts;

[0036] Compound surfactant: 10 - 20 parts;

[0037] Hydrophobic particles: 1 - 5 parts;

[0038] Polyether wetting aid: 5 - 10 parts.

[0039] To improve the performance of the defoaming composition at low temperatures, one is to improve the dispersibility and fluidity of the defoaming composition in a low-temperature environment; the other is to enhance the defoaming effect of the defoaming composition under low-temperature conditions. Therefore, the present application selects low-molecular-weight alkane-modified polysiloxane as the base material to ensure good fluidity and high dispersibility under low-temperature conditions; in addition, through the reasonable selection and formulation of a composite emulsifier system, the defoaming agent can still maintain excellent dispersibility and fluidity in a low-temperature environment. With the cooperation of hydrophobic particles and polyether wetting aids, the surface tension of the foam is further reduced, enabling the defoaming agent to quickly reach the gas-liquid interface of the foam and rapidly break down the foam, ensuring that the defoaming agent still maintains a rapid defoaming effect in a low-temperature environment. By continuously optimizing the proportions of low-molecular-weight alkane-modified polysiloxane, compound surfactant, hydrophobic particles, and wetting aids, the present application achieves rapid dispersion and high-efficiency defoaming in a low-temperature environment.

[0040] In one embodiment, the low-temperature rapid-dispersing silicone defoaming composition further comprises 1 - 3 parts by weight of a dispersant and / or synergist.

[0041] An appropriate amount of dispersant and / or synergist is selected, and the proportions of the various components are controlled to ensure the dispersibility and stability of the defoaming agent in the environment. By adding a dispersant to the formulation, it is ensured that the defoaming agent can form a uniform distribution at the gas-liquid interface and will not coagulate at low temperatures, increasing the dispersibility and fluidity.

[0042] In one embodiment, the structure of the low molecular weight alkane-modified polysiloxane is shown in Formula I:

[0043] (Formula I);

[0044] wherein R1 is an alkyl group with 2 - 8 carbon atoms; m = 1 - 50, and m is an integer.

[0045] The low molecular weight design can provide better fluidity in a low-temperature environment, ensuring that the defoamer can be quickly dispersed; at the same time, the low molecular weight siloxane chain is more flexible, capable of adapting to the viscosity changes in a low-temperature environment and ensuring that it is not easily solidified at low temperatures. The low molecular weight siloxane containing short-chain alkanes has higher fluidity and dispersibility compared to high molecular weight siloxanes, enabling the defoamer to quickly diffuse to the gas-liquid interface at low temperatures and effectively achieving the effect of rapid defoaming.

[0046] In one embodiment, the composite surfactant is a non-ionic and anionic composite surfactant.

[0047] In one embodiment, the non-ionic surfactant is one or a combination of two or more of ethoxylated and / or propoxylated fatty alcohols, ethoxylated and / or propoxylated glycerol ethers, alkyl polyethylene glycol ethers, polyethylene glycols, and polyvinyl alcohols;

[0048] The anionic surfactant is fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate and / or fatty alcohol polyoxyethylene / polyoxypropylene ether sulfonate.

[0049] In one embodiment, for the ethoxylated and / or propoxylated fatty alcohols, the ethoxylated and / or propoxylated fatty alcohols are Lutensol and Lutensol TO series from BASF; the molecular weight is 200 - 2000.

[0050] The ethoxylated and / or propoxylated glycerol ethers are Tegosurf series from Degussa; preferably, the ethoxylated and / or propoxylated glycerol ethers are ethoxylated glycerol monooleate (GMOE) and / or ethoxylated glycerol cocoate.

[0051] The alkyl polyethylene glycol ethers are Triton series from DuPont and / or Brij series from Croda; preferably, the alkyl polyethylene glycol ethers are Brij 35 and / or Triton X - 100.

[0052] The polyethylene glycol is Carbowax from Dow Chemical; preferably, the polyethylene glycol is PEG 400 - PEG 3350.

[0053] The polyvinyl alcohol is Clariant Mowiol; preferably, the polyvinyl alcohol is PVA 88-05 and / or PVA 24-88.

[0054] In one embodiment, the fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate is the Kao Chemicals Akypo LF series or the Stepan company Nansa series; preferably, the fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate is fatty alcohol polyoxyethylene (5EO) carboxylate and / or Akypo LF 2.

[0055] The fatty alcohol polyoxyethylene / polyoxypropylene ether sulfonate is Clariant Emulsogen APS and / or the BASF Hostapon series; preferably, the fatty alcohol polyoxyethylene / polyoxypropylene ether sulfonate is fatty alcohol polyoxyethylene (3EO) sulfonate and / or Emulsogen APS 164.

[0056] Non-ionic surfactants have good hydrophilicity and interfacial activity, and can dissolve rapidly and form a uniform distribution on the liquid surface under low-temperature environments; anionic surfactants enhance the stability of the defoamer at the gas-liquid interface and prevent the regeneration of foam. This composite surfactant system still has excellent surface activity under low-temperature conditions and can rapidly diffuse the defoaming composition to the foam surface. It can rapidly diffuse at the gas-liquid interface, form a stable interface, and effectively inhibit the regeneration of foam.

[0057] In one embodiment, the hydrophobically modified silica is fumed silica or precipitated silica modified with a modifier; the modifier is one or a combination of two or more of polydimethylsiloxane, polydimethylsilazane, long-chain alkylsilane, or phenylsilane. 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, Tokuyama DM-30 of Japan, Tokuyama DM-20S of Japan, Wacker H20 of Germany, or Wacker H30 of Germany.

[0058] In one embodiment, the modifier is one or a combination of two or more of hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, hexamethyldisilazane, hexadecyltrimethoxy(triethoxy)silane, octamethyltrimethoxy(triethoxy)silane, or phenyltrimethoxy(triethoxy)silane.

[0059] In this embodiment, the method for modifying silica is as follows:

[0060] The hydrophobic modification of silica can be carried out by heating and reacting fumed silica with a modifier under a catalyst. The catalyst is a silane coupling agent, such as KH-602, APMDS, etc. The reaction is carried out at 50-80 °C for 2-12 h.

[0061] In one embodiment, the polyether wetting aid is an organosilicon-modified polyether wetting agent; the structure of the organosilicon-modified polyether wetting agent is shown in Formula II:

[0062] (Formula II);

[0063] wherein R2 is an ethoxylated and / or propoxylated polyether group, and R3 and R4 are methyl, ethyl, ethoxylated and / or propoxylated polyether groups; the ethoxylated and / or propoxylated polyether group has a structure of -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e = 5-10, f = 0-30, g = 3-5, and e, f, and g are integers; k = 1-10, and k is an integer.

[0064] A small amount of polyether wetting aids can make the defoamer reach the gas-liquid interface more quickly by reducing the surface tension. Polyether wetting agents can still effectively reduce the surface tension at low temperatures, making the defoamer more easily distributed at the gas-liquid interface. The addition of organosilicon-modified polyether wetting agents further enhances the rapid defoaming effect of the defoamer in low-temperature environments and can also effectively inhibit foam regeneration.

[0065] In one embodiment, the structures of the dispersant and synergist are shown in Formula III:

[0066] (Formula III);

[0067] wherein R5 is a polyether or polyether ester, and R6 is an alkyl or aryl group; p = 0-100, q = 0-100, and p and q are integers, where p and q are not both 0 at the same time.

[0068] In one embodiment, R5 is -CH2-CH2-CH2-O-[(CH2-CH2-O) u ⋅(CH2-CH(CH3)-O) v-R7; u = 0 - 10, v = 10 - 30, and u and v are integers; R7 is H or R8-CO- with a carbonyl group, where R8 is any one of methyl, ethyl, propyl, butyl, and stearyl. In one embodiment, the R6 is an alkane with 8, 10, 12, 14, 16, or 18 carbon atoms, or is phenethyl or methylphenethyl.

[0069] The optimized design of the dispersant and synergist for the polysiloxane chain segment and grafting group enables it to provide both rapid defoaming ability and maintain the foam suppression effect for a long time, meeting the industrial requirements in low-temperature environments.

[0070] The embodiment of the present application also provides a preparation method for a low-temperature rapid-dispersing silicone defoaming composition, including the following steps:

[0071] S1. Weigh low-molecular-weight alkane-modified polysiloxane, composite surfactant, hydrophobic particles, and polyether wetting aid in proportion, and sequentially add them to a stirring container;

[0072] S2. Start the stirring equipment, and under the condition of low-speed stirring, gradually mix each component evenly;

[0073] S3. After mixing evenly, slowly add the dispersant and synergist, continue to stir, and gradually increase the stirring speed to form a uniform and stable dispersion in the whole system;

[0074] S4. The whole stirring process needs to last for a certain period of time until all components of the defoaming composition are completely fused and there is no obvious stratification or particle precipitation.

[0075] In one embodiment, in step S2, the low-speed stirring rate is 200 - 500 rpm.

[0076] In one embodiment, in step S3, the stirring speed is 1000 - 2500 rpm; the temperature in step S3 is controlled at 20 - 25°C. During this process, it is necessary to ensure that the temperature is controlled within an appropriate range to avoid affecting the performance of each component and the effect of the final product due to too high or too low temperature;

[0077] The following is further illustrated with specific examples.

[0078] Example 1

[0079] A low-temperature rapid-dispersing silicone defoaming composition, including the following components by weight:

[0080] 70 parts of low-molecular-weight alkane-modified polysiloxane, 15 parts of composite surfactant, 5 parts of hydrophobic particles; 8 parts of polyether wetting aid; 2 parts of dispersant;

[0081] The low-molecular-weight alkane-modified polysiloxane is shown in Formula I, wherein R1 is an ethyl group; m is 25;

[0082] The composite surfactant is polyethylene glycol PEG 400 and polyoxyethylene (8) octyl carboxylate in a mass ratio of 1:1;

[0083] The polyether wetting aid is shown in Formula II, wherein R3 and R4 are methyl groups; the structure of R2 is -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e = 10, f = 10, g = 4; k = 5;

[0084] The dispersant is shown in Formula III, wherein R5 has a structure of -CH2-CH2-CH2-O-[(CH2-CH2-O) u ⋅(CH2-CH(CH3)-O) v -H; u = 5, v = 20;; R6 is an octyl group; p = 20, q = 30.

[0085] The hydrophobic modified silica is prepared by reacting fumed silica with decamethyltetrasiloxane in the presence of a silane coupling agent KH-602 at a mass ratio of 10:3:2 at 70 °C for 10 h;

[0086] It is prepared by the following method:

[0087] Weigh the low-molecular-weight alkane-modified polysiloxane, composite surfactant, hydrophobic particles and polyether wetting aid in proportion, and add them to the stirring container in sequence; start the stirring equipment and stir at 200 - 500 rpm to gradually mix the components evenly;

[0088] After mixing evenly, slowly add the dispersant and synergist, continue stirring, control the temperature at 20 - 25 °C, and gradually increase the stirring speed to 1000 - 2500 rpm to form a uniform and stable dispersion liquid for the whole system;

[0089] The whole stirring process needs to last for a certain time until the components of the defoaming composition are completely fused and there is no obvious layering or particle precipitation, obtaining the low-temperature rapid-dispersing silicone defoaming composition with a viscosity of 100 - 300 cst.

[0090] Example 2

[0091] A low-temperature rapid-dispersing silicone defoaming composition, comprising the following components by weight:

[0092] 60 parts of low-molecular-weight alkane-modified polysiloxane, 20 parts of composite surfactant, 3 parts of hydrophobic particles; 5 parts of polyether wetting aid; 1 part of dispersant;

[0093] The low-molecular-weight alkane-modified polysiloxane is shown in Formula I, where R1 is propyl; m is 5;

[0094] The composite surfactant is polyvinyl alcohol PVVA88-05 and Emulsogen APS 164 with a mass ratio of 2:1;

[0095] The polyether wetting aid is shown in Formula II, where R3 is ethyl, and the structures of R4 and R2 are -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e = 5, f = 10, g = 5; k = 10;

[0096] The dispersant is shown in Formula III, where the structure of R5 is -CH2-CH2-CH2-O-[(CH2-CH2-O) u ⋅(CH2-CH(CH3)-O) v -OCR8; u = 0, v = 30; where R8 is ethyl;; p = 50, q = 0.

[0097] The hydrophobic modified silica is prepared by reacting fumed silica with cetyltrimethoxy(triethoxy)silane in the presence of the silane coupling agent APMDS at a mass ratio of 10:4:1.5 at 50 °C for 12 h;

[0098] The preparation method is the same as that of Example 1, and the viscosity is 100-300 cst.

[0099] Example 3

[0100] A low-temperature and fast-dispersing silicone defoaming composition, comprising the following components by weight:

[0101] 75 parts of low-molecular-weight alkane-modified polysiloxane, 10 parts of composite surfactant, 1 part of hydrophobic particles; 10 parts of polyether wetting aid; 3 parts of dispersant;

[0102] The low-molecular-weight alkane-modified polysiloxane is shown in Formula I, where R1 is octyl; m is 45;

[0103] The composite surfactant is Triton X-100 and sodium alcohol polyoxyethylene ether carboxylate with a mass ratio of 3:1;

[0104] The polyether wetting aid is shown in Formula II, where R3 is methyl and R4 is ethyl; the structure of R2 is -(CH2) g (OCH2CH2) e (OCH2CH2CH2) fOH, e = 8, f = 25, g = 3; k = 1;

[0105] The dispersant is as shown in Formula III, wherein the structure of R5 is -CH2-CH2-CH2-O-[(CH2-CH2-O) u ⋅(CH2-CH(CH3)-O) v -OCR8; u = 10, v = 10; R8 is butyl; R6 is phenethyl; p = 20, q = 30.

[0106] The hydrophobically modified silica is prepared by reacting fumed silica with phenyltrimethoxy(triethoxy)silane in the presence of the silane coupling agent KH-602 at a mass ratio of 10:2:1 at 80 °C for 2 h;

[0107] The preparation method is the same as that of Example 1, and the viscosity is 100 - 300 cst.

[0108] Comparative Example 1 (high molecular weight)

[0109] The difference between Comparative Example 1 and Example 1 is that 70 parts of polydimethylsiloxane with a viscosity of 1000 cst at 25 °C is replaced by 70 parts of low molecular weight alkane-modified polysiloxane; the composition of other substances and the preparation method are the same as those of Example 1.

[0110] Comparative Example 2 (single surfactant)

[0111] The difference between Comparative Example 2 and Example 1 is that 15 parts of polyethylene glycol is replaced by 15 parts of composite surfactant; the composition of other substances and the preparation method are the same as those of Example 1.

[0112] Comparative Example 3 (single surfactant)

[0113] The difference between Comparative Example 3 and Example 1 is that 15 parts of sodium C12 alkyl alcohol polyoxyethylene / polyoxypropylene ether carboxylate is replaced by 15 parts of composite surfactant; the composition of other substances and the preparation method are the same as those of Example 1.

[0114] Comparative Example 4 (unmodified silica, decreased defoaming performance)

[0115] The difference between Comparative Example 4 and Example 1 is that 5 parts of fumed silica is replaced by 5 parts of hydrophobic particles; the composition of other substances and the preparation method are the same as those of Example 1.

[0116] Comparative Example 5 (without dispersant, decreased defoaming performance)

[0117] The difference between Comparative Example 5 and Example 1 is that it does not contain a dispersant; the composition of other substances and the preparation method are the same as those of Example 1.

[0118] Comparative Example 6 (without polyether wetting agent, decreased defoaming performance)

[0119] The difference between Comparative Example 6 and Example 1 is that it does not contain a polyether wetting aid; the compositions of other substances and the preparation method are the same as those of Example 1.

[0120] Test Example:

[0121] Test Method:

[0122] (1) Using white water from the paper industry as the test medium, the test sample foam was prepared to the same height by blowing air; the defoaming composition was added, and the times when the foam reached 50%, 20%, and completely disappeared were recorded. The longer the time required, the worse the foam inhibition performance of the sample; the foam regeneration situation was recorded.

[0123] Test Conditions: Test temperature 5°C; dosage of white water from the paper industry: 200 ml; dosage of samples of Examples 1-3 and Comparative Examples 1-6: 30 μL; test flow rate: 5 L / min. The results are shown in Table 1;

[0124] Table 1 Test Results Table

[0125]

[0126] (2) Using the fermentation broth during beer fermentation as the test medium, the test sample foam was prepared to the same height by blowing air; the defoaming composition was added, and the times when the foam reached 50%, 20%, and 0% in volume were recorded. The longer the time required, the worse the foam inhibition performance of the sample.

[0127] Test Conditions: Test temperature 15°C; dosage of fermentation broth during beer fermentation: 200 ml; dosage of samples of Examples 1-3 and Comparative Examples 1-6: 30 μL; test flow rate: 5 L / min. The results are shown in Table 2;

[0128] Table 2 Test Results Table

[0129]

[0130] It can be seen from Examples 1-3 in Table 1 and Table 2 that at 5°C, the defoamers of Examples 1-3 can completely eliminate the foam generated from white water in the paper industry and the fermentation broth during beer fermentation in less than about 1.5 minutes. However, for Comparative Examples 1-6, the time required to achieve the same effect is longer, and the time taken to completely defoam the foam is longer than that of the examples, indicating that the defoaming performance of the defoamers is inferior to that of the examples.

[0131] Comparative Example 1 selected a high molecular weight alkane-modified polysiloxane, which was polydimethylsiloxane with a viscosity of 1000 cst at 25°C. The defoaming time in the white water of the paper industry at 5°C reached 4 minutes. In the fermentation broth during beer fermentation at 15°C, as the temperature increased, the defoaming time shortened to 3'49'', indicating that the decrease in temperature had a certain impact on the defoaming performance of the defoaming composition in Comparative Example 1. The defoaming times of the defoaming compositions of Examples 1-3 in the white water of the paper industry at 5°C and in the fermentation broth during beer fermentation at 15°C were basically the same, indicating that when the temperature decreased from 15°C to 5°C, the defoaming performance of the defoaming compositions of Examples 1-3 basically did not change, and the defoaming compositions exhibited excellent low-temperature defoaming performance. Moreover, after the defoaming compositions of Examples 1-3 were used, the foam would not regenerate within 15 minutes. After the defoaming composition of Comparative Example 1 was used, there was still slight foam regeneration within 5 minutes after the foam was eliminated, which also indicated that the defoaming compositions of Examples 1-3 had a better foam suppression effect than Comparative Example 1.

[0132] In Comparative Example 2 and Comparative Example 3, a single non-ionic surfactant and an anionic surfactant were used respectively, and the foam elimination time of the defoaming composition increased compared with that of the examples, indicating that the use of a composite surfactant in the examples, in combination with a low molecular weight alkane-modified polysiloxane, could significantly improve the defoaming performance. Comparative Example 4 showed that the hydrophobic modification of silica, as a structural aid, could improve the dispersibility and adhesion of the defoaming agent; and enable it to stably exist at low temperatures, enhance the adhesion of the defoaming agent, and thus strengthen the defoaming performance.

[0133] Comparative Example 5 showed that the dispersant ensured that the defoaming agent could form a uniform distribution at the gas-liquid interface and would not coagulate at low temperatures, which also helped the defoaming agent to play a defoaming role. However, the effect of Comparative Example 5 was better than that of Comparative Examples 1-4 and Comparative Example 6, indicating that the dispersant could be added as an auxiliary aid.

[0134] In Tables 1 and 2, the defoaming effects of Comparative Example 6 were equivalent, indicating that the polyether wetting aid helped to further enhance the defoaming speed of the defoaming agent in a low-temperature environment, enabling the defoaming agent to achieve rapid defoaming within dozens of seconds.

[0135] In summary, the present application uses a low-molecular-weight polydimethylsiloxane containing short-chain alkanes as the base material to ensure good fluidity and high dispersion ability of the defoaming composition at low temperatures; through the reasonable selection and formulation of a composite surfactant, the defoaming composition can rapidly diffuse at the gas-liquid interface to form a stable interface, and still maintain excellent dispersibility and fluidity in a low-temperature environment, effectively inhibiting the re-generation of foam. An appropriate amount of polyether wetting agent and hydrophobic particles further reduce the surface tension of the foam, enabling the defoaming agent to quickly reach the gas-liquid interface of the foam and rapidly disintegrate the foam, ensuring that the defoaming agent still maintains a rapid defoaming effect in a low-temperature environment; rapid dispersion and high-efficiency defoaming in a low-temperature environment are achieved.

[0136] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. 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. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0137] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0138] As described above, the above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of various changes or substitutions, and these should all be covered by 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 fast dispersible silicone defoaming composition, characterized in that: It includes the following components in parts by weight: Low molecular weight alkane modified polysiloxane: 60-75 parts; Composite surfactant: 10-20 parts; Hydrophobic particles: 1-5 parts; Polyether wetting agent: 5-10 parts; Dispersant: 1-3 parts; Wherein, the structure of the low molecular weight alkane-modified polysiloxane is shown in Formula I: (Formula I); Wherein R1 is a C2-C8 alkyl group; m=1-50, and m is an integer; The composite surfactant is a nonionic and anionic composite surfactant; the nonionic surfactant is one or a combination of two or more of ethoxylated and / or propoxylated fatty alcohols, ethoxylated and / or propoxylated glycerol ethers, alkyl polyethylene glycol ethers, polyethylene glycol, and polyvinyl alcohol; the anionic surfactant is a fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate and / or a fatty alcohol polyoxyethylene / polyoxypropylene ether sulfonate; The hydrophobic particles are fumed silica or precipitated silica modified by a modifier; the modifier is one or a combination of two or more of polydimethylsiloxane, polydimethylsilazane, long-chain alkyl silane or phenyl silane; the modifier is one or a combination of two or more of hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, hexamethyldisilazane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octamethyltrimethoxysilane, octamethyltriethoxysilane, phenyltriethoxysilane or phenyltrimethoxysilane; The polyether wetting aid is an organosilicon-modified polyether wetting agent; the structure of the organosilicon-modified polyether wetting agent is shown in Formula II: (Formula II); Wherein R2 is an ethoxylated and / or propoxylated polyether group, R3 and R4 are methyl, ethyl, ethoxylated and / or propoxylated polyether groups; ethoxylated and / or propoxylated polyether groups have the structure -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e=5-10, f=0-30, g=3-5, and e, f, g are integers; k=1-10, and k is an integer; The structure of the dispersant is shown in Formula III: (Formula III); Wherein R5 is polyether or polyether ester, R6 is alkyl or aromatic hydrocarbon group; p=0-100, q=0-100, and p and q are integers, wherein p and q are not 0 at the same time.

2. A method for preparing a fast dispersible silicone defoaming composition, characterized in that: The following steps are involved: S1, weighing low molecular weight alkane-modified polysiloxane, composite surfactant, hydrophobic particles and polyether wetting aid according to proportion, and adding them into a stirring container in sequence; S2, start the stirring equipment, and gradually mix the components evenly under low-speed stirring conditions; S3. After mixing evenly, slowly add the dispersant, continue stirring, and gradually increase the stirring speed to make the whole system form a uniform and stable dispersion; S4. The entire stirring process needs to be continued for a certain period of time until the components of the defoaming composition are completely blended and there is no obvious stratification or particle precipitation, thereby obtaining the fast-dispersing organosilicon defoaming composition.

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