Low-temperature rapid dispersion type organic silicon defoaming composition and preparation method thereof

Abstract

The invention provides a low-temperature fast dispersing type organic silicon defoaming composition and a preparation method thereof, and the low-temperature fast dispersing type organic silicon defoaming composition comprises low-molecular-weight alkane modified polysiloxane, a composite surfactant, hydrophobic particles and a polyether wetting auxiliary agent. Good flowability and relatively high dispersing capacity of the defoaming composition under a low-temperature condition are ensured; the nonionic and anionic composite surfactants, the polyether wetting auxiliary agent, the hydrophobic particles and the dispersing agent are matched, so that the dispersity and the flowability of the defoaming composition in a low-temperature environment are further enhanced, and the surface tension of foam is reduced; the defoaming composition can be quickly diffused on a gas-liquid interface, quickly reaches the gas-liquid interface of foam and quickly collapses the foam, so that the defoaming agent is ensured to still keep a quick defoaming effect in a low-temperature environment.

Description

Technical Field

[0001] The present application belongs to the technical field of fine chemicals, and in particular relates to a low-temperature fast-dispersible organosilicon defoaming composition and a preparation method thereof. Background Art

[0002] In modern industrial production, the foam problem in low-temperature environments is particularly prominent, especially in the papermaking industry, food processing, fermentation tank production and other processes. Low-temperature foam will bring a series of production problems. Taking papermaking as an example, a large amount of foam will be generated in the pulp white water at a temperature of 5-10°C. If the foam is not eliminated quickly, it will not only affect the product quality, but also hinder the smoothness of the transmission pipeline and affect the normal operation of the equipment. At the same time, in the process of food processing and fermentation, foam is also prone to cause health and safety problems. Foam hinders the flow of liquid, which may lead to uneven product quality, increase the difficulty of production control and production time cost.

[0003] Traditional silicone defoamers work well at room temperature, but they have poor dispersibility under low temperature conditions, which makes it difficult for the defoamer to quickly reach the gas-liquid interface, and the defoaming effect decreases. 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 to the foam surface and unable to work quickly. For this reason, the development of a silicone defoamer that can quickly disperse and efficiently defoam under low temperature conditions has become an urgent need in production. This can not only solve the foam problem in the low temperature process, but also improve the overall production efficiency and product quality. Summary of the invention

[0004] The present application provides a low-temperature, fast-dispersing silicone defoaming composition and a preparation method thereof to solve the problems existing in the related art. The technical solution is as follows:

[0005] In a first aspect, the present invention provides a low-temperature fast-dispersing silicone defoaming composition, comprising the following components in parts by weight:

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

[0007] Composite surfactant: 10-20 parts;

[0008] Hydrophobic particles: 1-5 parts;

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

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

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

[0012]

[0013] Wherein R1 is a C2-C8 alkyl group; m=1-50, and m is an integer.

[0014] In one embodiment, the complex surfactant is a nonionic and anionic complex 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 glycol, and polyvinyl alcohol;

[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 by a modifier; the modifier is one or a combination of two or more of polydimethylsiloxane, polydimethylsilazane, long-chain alkyl silane or phenyl silane.

[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 a silicone-modified polyether wetting agent; the structure of the silicone-modified polyether wetting agent is shown in Formula II:

[0020]

[0021] 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.

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

[0023]

[0024] 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.

[0025] In a second aspect, the present invention provides a method for preparing a low-temperature fast-dispersing silicone defoaming composition, comprising the following steps:

[0026] 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;

[0027] S2, start the stirring equipment, and gradually mix the components evenly under low-speed stirring conditions;

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

[0029] 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 low-temperature fast-dispersing organosilicon defoaming composition.

[0030] The advantages or beneficial effects of the above technical solution include at least:

[0031] The present invention discloses a low-temperature fast-dispersible silicone defoaming composition, which includes a low-molecular-weight alkane-modified polysiloxane, a composite surfactant, hydrophobic particles and a polyether wetting agent. The low-molecular-weight alkane-modified polysiloxane is used as the basic material to ensure the good fluidity and high dispersibility 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 maintain excellent dispersibility and fluidity under low-temperature conditions, but also can quickly diffuse at the gas-liquid interface to form a stable interface, effectively inhibiting the regeneration of foam; and the polyether wetting agent further reduces the surface tension of the foam, so that the defoaming agent can quickly reach the gas-liquid interface of the foam, quickly disintegrate the foam, and ensure that the defoaming agent still maintains a fast defoaming effect under low-temperature conditions. Modified fumed silica, as a synergist and structural stabilizer, can improve the dispersibility and adhesion of the defoaming agent; by continuously optimizing the ratio of low-molecular-weight polysiloxane, composite surfactant, hydrophobic particles and polyether wetting agents, the present invention achieves rapid dispersion and efficient defoaming under low-temperature conditions.

[0032] The above summary is for illustrative purposes only 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 be readily apparent by reference to the following detailed description. DETAILED DESCRIPTION

[0033] Hereinafter, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the following description is considered to be exemplary and non-restrictive in nature.

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

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

[0036] Composite 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, first, the dispersibility and fluidity of the defoaming composition in a low temperature environment are improved; second, the defoaming effect of the defoaming composition under low temperature conditions is enhanced. 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 the composite emulsifier system, the defoaming agent can still maintain excellent dispersibility and fluidity under low temperature conditions. In combination with hydrophobic particles and polyether wetting aids, the surface tension of the foam is further reduced, so that the defoaming agent can quickly reach the gas-liquid interface of the foam, quickly disintegrate the foam, and ensure that the defoaming agent still maintains a rapid defoaming effect under low temperature conditions. By continuously optimizing the ratio of low molecular weight alkane-modified polysiloxane, composite surfactant, hydrophobic particles and wetting aid, the present application achieves rapid dispersion and efficient defoaming under low temperature environments.

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

[0041] Select the appropriate amount of dispersant and / or synergist, and control the proportion of each component to ensure the dispersibility and stability of the defoamer in the environment. By adding dispersant to the formula, it is ensured that the defoamer can be evenly distributed at the gas-liquid interface, will not condense at low temperatures, and increase dispersibility and fluidity.

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

[0043]

[0044] Wherein R1 is a C2-C8 alkyl group; m=1-50, and m is an integer.

[0045] The low molecular weight design can provide better fluidity in low temperature environments, ensuring that the defoamer can be quickly dispersed; at the same time, the low molecular weight siloxane chain is more flexible, can adapt to the viscosity changes in low temperature environments, and ensure that it is not easy to solidify at low temperatures. Low molecular weight siloxane containing short chain alkanes has higher fluidity and dispersibility than high molecular weight siloxane, allowing the defoamer to quickly diffuse to the gas-liquid interface at low temperatures, effectively achieving the effect of rapid defoaming.

[0046] In one embodiment, the complex surfactant is a nonionic and anionic complex surfactant.

[0047] 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 glycol, and polyvinyl alcohol;

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

[0049] In one embodiment, the ethoxylated and / or propoxylated fatty alcohol is BASF's Lutensol and Lutensol TO series, with a molecular weight of 200-2000.

[0050] The ethoxylated and / or propoxylated glyceryl ether is Tegosurf series; preferably, the ethoxylated and / or propoxylated glyceryl ether is ethoxylated glyceryl monooleate (GMOE) and / or ethoxylated glyceryl coconut oil ester.

[0051] The alkyl polyethylene glycol ether is DuPont Triton series and / or Croda Brij series; preferably, the alkyl polyethylene glycol ether is 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 PVA24-88.

[0054] In one embodiment, the fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate is Kao Chemicals Akypo LF series or Stepan 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 BASF Hostapon series; preferably, the fatty alcohol polyoxyethylene / polyoxypropylene ether sulfonate is fatty alcohol polyoxyethylene (3EO) sulfonate and / or Emulsogen APS164.

[0056] Nonionic surfactants have good hydrophilicity and interfacial activity. They can dissolve quickly and form a uniform distribution on the liquid surface under low temperature conditions. 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 quickly diffuse the defoaming composition to the foam surface. It can quickly diffuse at the gas-liquid interface to form a stable interface and effectively inhibit the regeneration of foam.

[0057] In one embodiment, 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 alkyl silane or phenyl silane. 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, CabotTS 610, CabotTS 530, Japan Tokuyama DM30, Japan Tokuyama DM20S, Germany Wacker H20 or Germany Wacker H30.

[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 of modifying silica is:

[0060] The silica can be hydrophobically modified by heating the fumed silica and the 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 and the reaction time is 2-12 hours.

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

[0062]

[0063] 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.

[0064] A small amount of polyether wetting agents can reduce surface tension, allowing the defoamer to reach the gas-liquid interface more quickly. Polyether wetting agents can still effectively reduce surface tension at low temperatures, making it easier for the defoamer to distribute on the gas-liquid interface. The addition of silicone-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 as shown in Formula III:

[0066]

[0067] 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.

[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, wherein R8 is any one of methyl, ethyl, propyl, butyl, and stearyl. In one embodiment, R6 is an alkane having 8, 10, 12, 14, 16, or 18 carbon atoms, or is phenethyl or methylphenethyl.

[0069] The optimized design of dispersants and synergists for polysiloxane chain segments and grafted groups enables them to provide rapid defoaming ability and maintain the antifoaming effect for a long time, meeting industrial needs in low temperature environments.

[0070] The present application also provides a method for preparing a low-temperature fast-dispersing silicone defoaming composition, comprising the following steps:

[0071] 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;

[0072] S2, start the stirring equipment, and gradually mix the components evenly under low-speed stirring conditions;

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

[0074] S4. The entire stirring process needs to continue 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.

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

[0076] In one embodiment, in step S3, the stirring speed is 1000-2500 rpm; the temperature of step S3 is controlled at 20-25° C. In 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 excessively high or low temperature;

[0077] The following is a further description with reference to specific embodiments.

[0078] Example 1

[0079] A low-temperature fast-dispersing organosilicon defoaming composition comprises the following components in parts 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 ethyl; m is 25;

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

[0083] The polyether wetting agent 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 is a structure of -CH2-CH2-CH2-O-[(CH2-CH2-O) u (CH2-CH(CH3)-O) v ]-H; u=5, v=20; ; R6 is octyl; p=20, q=30.

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

[0086] Prepared by the following method:

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

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

[0089] The entire stirring process needs to be continued for a certain period of time until the components of the defoaming composition are completely fused and there is no obvious stratification or particle precipitation, thereby obtaining the low-temperature fast-dispersible silicone defoaming composition with a viscosity of 100-300 cst.

[0090] Example 2

[0091] A low-temperature fast-dispersing organosilicon defoaming composition comprises the following components in parts 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, wherein R1 is a propyl group; m is 5;

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

[0095] The polyether wetting agent is shown in formula II, wherein R3 is ethyl, and the structure of R4 and R2 is -(CH2) g (OCH2CH2) e (OCH2CH2CH2) f OH, e=5, f=10, g=5; k=10;

[0096] The dispersant is 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=0, v=30; wherein R8 is ethyl; ; p=50, q=0.

[0097] The hydrophobically modified silica is prepared by reacting fumed silica and hexadecyltrimethoxy (triethoxy) silane in the presence of a silane coupling agent APMDS at a mass ratio of 10:4:1.5 at 50°C for 12 hours.

[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 fast-dispersing organosilicon defoaming composition comprises the following components in parts 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, wherein R1 is octyl; m is 45;

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

[0104] The polyether wetting agent is shown in formula II, wherein R3 is methyl, R4 is ethyl; and R2 is -(CH2) g (OCH2CH2) e (OCH2CH2CH2) fOH, e=8, f=25, g=3; k=1;

[0105] The dispersant is 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 and phenyltrimethoxy (triethoxy) silane in the presence of silane coupling agent KH-602 at a mass ratio of 10:2:1 at 80°C for 2h.

[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. replaces 70 parts of low molecular weight alkane-modified polysiloxane; the other material compositions and preparation methods 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 replace 15 parts of the complex surfactant; the other material compositions and preparation methods 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 C12 alkyl alcohol polyoxyethylene / polyoxypropylene ether carboxylate sodium replaces 15 parts of the composite surfactant; the other material compositions and preparation methods are the same as those in Example 1.

[0114] Comparative Example 4 (Silicon dioxide is not modified, and defoaming performance decreases)

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

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

[0117] The difference between Comparative Example 5 and Example 1 is that no dispersant is contained; other material compositions and preparation methods are the same as those of Example 1.

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

[0119] The difference between Comparative Example 6 and Example 1 is that the polyether wetting aid is not contained; the other material compositions and preparation methods are the same as those of Example 1.

[0120] Test example:

[0121] Test method:

[0122] (1) Using papermaking industrial white water as the test medium, prepare the test sample foam to the same height by aeration; add the defoaming composition, and record the time for the foam to reach 50%, 20%, and completely disappear. The longer the time required, the worse the anti-foaming performance of the sample; record the foam regeneration situation

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

[0124] Table 1 Test results

[0125] Foam volume 50％ 20％ 0％ Repeated foaming Example 1 36″ 58″ 1′23″ No foaming within 15 minutes Example 2 38″ 59″ 1′25″ No foaming within 15 minutes Example 3 38″ 60″ 1′25″ No foaming within 15 minutes Comparative Example 1 1′05″ 2′21″ 4′02″ Slight foam regeneration within 5 minutes Comparative Example 2 51″ 1′42″ 2′36″ No foaming within 15 minutes Comparative Example 3 58″ 1′57″ 3′01″ Slight foam regeneration within 10 minutes Comparative Example 4 53″ 1′37″ 2′32′ No foaming within 15 minutes Comparative Example 5 42″ 1′16″ 1′48″ No foaming within 15 minutes Comparative Example 6 49″ 1′31″ 2′32″ No foaming within 15 minutes

[0126] (2) Using the fermentation liquid in the beer fermentation process as the test medium, the foam of the test sample was prepared to the same height by aeration; adding the defoaming composition, and recording the time when the foam reached 50%, 20%, and 0% volume. The longer the time required, the worse the antifoaming performance of the sample.

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

[0128] Table 2 Test results

[0129] Foam volume 50％ 20％ 0％ Repeated foaming Example 1 35″ 55″ 1′20″ No foaming within 15 minutes Example 2 36″ 57″ 1′21″ No foaming within 15 minutes Example 3 35″ 58″ 1′22″ No foaming within 15 minutes Comparative Example 1 58″ 2′01″ 3′49″ Slight foam regeneration within 5 minutes Comparative Example 2 49″ 1′35″ 2′21″ No foaming within 15 minutes Comparative Example 3 57″ 1′51″ 2′48″ Slight foam regeneration within 10 minutes Comparative Example 4 51″ 1′29″ 2′11′ No foaming within 15 minutes Comparative Example 5 41″ 1′14″ 1′40″ No foaming within 15 minutes Comparative Example 6 48″ 1′31″ 2′30″ No foaming within 15 minutes

[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 by the white water of the papermaking industry and the fermentation liquid during the beer fermentation process in less than 1.5 minutes, while Comparative Examples 1-6 take a longer time to achieve the same effect and completely defoam the foam, which means that the defoaming performance of the defoamers is not as good as that of the examples.

[0131] Comparative Example 1 selects a high molecular weight alkane-modified polysiloxane, which is a polydimethylsiloxane with a viscosity of 1000 cst at 25°C. The defoaming time in 5°C papermaking industrial white water reaches 4 minutes, while in the fermentation broth during beer fermentation at 15°C, the temperature rises and the defoaming time is shortened to 3'49", which shows that the defoaming performance of the defoaming composition of Comparative Example 1 is affected to a certain extent by the decrease in temperature. The defoaming time of the defoaming composition of Examples 1-3 in 5°C papermaking industrial white water and the defoaming time in the fermentation broth during beer fermentation at 15°C are basically the same, indicating that the defoaming performance of the defoaming composition of Examples 1-3 is basically unchanged from 15°C to 5°C, and the defoaming composition exhibits excellent low-temperature defoaming performance. In addition, after the defoaming composition of Examples 1-3 is used, the foam will not regenerate within 15 minutes, while after the defoaming composition of Comparative Example 1 is used, after the foam is eliminated, there is slight foam regeneration within 5 minutes, which also shows that the defoaming composition of Examples 1-3 has a better anti-foaming effect than Comparative Example 1.

[0132] Comparative Examples 2 and 3 respectively use a single nonionic surfactant and anionic surfactant, and the defoaming composition takes longer to eliminate foam than the example, indicating that the use of a composite surfactant in the example and a low molecular weight alkane-modified polysiloxane can significantly improve the defoaming performance. Comparative Example 4 illustrates that the hydrophobic modification of silica, as a structural additive, can improve the dispersibility and adhesion of the defoamer; and enable it to exist stably at low temperatures, improve the adhesion of the defoamer, and thus enhance the defoaming performance.

[0133] Comparative Example 5 shows that the dispersant ensures that the defoamer can be evenly distributed at the gas-liquid interface and will not condense at low temperatures, which also helps the defoamer to play a defoaming role. However, the effect of Comparative Example 5 is better than that of Comparative Examples 1-4 and Comparative Example 6, indicating that the dispersant can be added as an auxiliary agent.

[0134] In Table 1 and Table 2, the defoaming effect of Comparative Example 6 is comparable, indicating that the polyether wetting aid helps to further enhance the defoaming speed of the defoaming agent in a low temperature environment, enabling the defoaming agent to achieve rapid defoaming within tens of seconds.

[0135] In summary, the present application uses low molecular weight short-chain alkane-containing polydimethylsiloxane as the basic material to ensure good fluidity and high dispersibility of the defoaming composition under low temperature conditions; through the reasonable selection and deployment of the composite surfactant, the defoaming composition can diffuse rapidly at the gas-liquid interface to form a stable interface, and can still maintain excellent dispersibility and fluidity under low temperature conditions, effectively inhibiting the regeneration of foam. An appropriate amount of polyether wetting aids and hydrophobic particles further reduce the surface tension of the foam, allowing the defoaming agent to quickly reach the gas-liquid interface of the foam, quickly disintegrate the foam, and ensure that the defoaming agent still maintains a rapid defoaming effect under low temperature conditions; rapid dispersion and efficient defoaming under low temperature conditions 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" means that the specific features, structures, materials or characteristics described in conjunction 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0137] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0138] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A low-temperature fast-dispersing silicone defoaming composition, characterized in that: It includes the following components in parts by weight:

2. A low-temperature fast-dispersible organosilicon defoaming composition according to claim 1, characterized in that: The low-temperature fast-dispersing organosilicon defoaming composition further comprises 1 to 3 parts by weight of a dispersant and / or a synergist.

3. A low-temperature fast-dispersible organosilicon defoaming composition according to claim 1 or 2, characterized in that: The structure of the low molecular weight alkane-modified polysiloxane is shown in Formula I: Wherein R1 is a C2-C8 alkyl group; m=1-50, and m is an integer.

4. A low-temperature fast-dispersible organosilicon defoaming composition according to claim 1 or 2, characterized in that: The composite surfactant is a nonionic and anionic composite surfactant.

5. A low-temperature fast-dispersible organosilicon defoaming composition according to claim 4, characterized in that: 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 fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate and / or fatty alcohol polyoxyethylene / polyoxypropylene ether sulfonate.

6. A low-temperature fast-dispersible organosilicon defoaming composition according to claim 1 or 2, characterized in that: The hydrophobically modified silica is 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.

7. A low-temperature fast-dispersible organosilicon defoaming composition according to claim 6, characterized in that: 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.

8. A low-temperature fast-dispersible organosilicon defoaming composition according to claim 1 or 2, characterized in that: 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: 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.

9. The low-temperature fast-dispersible organosilicon defoaming composition according to claim 2, characterized in that: The structures of the dispersant and synergist are shown in 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.

10. A method for preparing a low-temperature fast-dispersing organosilicon 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 dispersant and synergist, 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 low-temperature fast-dispersing organosilicon defoaming composition.

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