A defoaming agent with fast dispersion, low cloud point, high temperature and pressure resistance, strong acid and strong base resistance

Abstract

The present application discloses a kind of dispersing fast, low turbidity, high temperature and high pressure resistant, strong acid and strong alkali defoaming agent, which is prepared from the following components: 5-50% of white carbon black silica paste, 1-25% of capped polyether modified polysiloxane, 0.1-10% of spherical poly siesquioxane, 1-25% of compound polyether, 0.1-10% of thickening agent, 0.05-0.5% of sterilizing agent, and the balance of water, wherein the sum of the weight percentages of the components is 100%. The present application also provides a production process of the defoaming agent, which comprises the following steps: stirring the white carbon black silica paste, spherical poly siesquioxane and capped polyether modified polysiloxane with a homogenizer to mix them thoroughly, then adding the compound polyether, thickening agent and sterilizing agent, stirring them uniformly, and continuing to stir them rapidly with the homogenizer for 25-35 minutes to obtain the mixed uniform polyether modified polysiloxane defoaming agent. The purpose of the present application is to provide a defoaming agent with fast dispersion speed, low turbidity, high temperature and high pressure resistance, and strong acid and strong alkali resistance.

Description

Technical Field

[0001] The invention relates to the technical field of defoaming agents, and in particular to a defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, and strong acid and alkali resistance. Background Art

[0002] In recent years, polyether-modified polysiloxanes have become a hot topic in research and development both domestically and internationally. Through polyether grafting or block modification, the synergistic properties of the two components are exploited: the hydrophilic polyether segment imparts self-emulsification, while the hydrophobic polysiloxane segment imparts low surface tension, reducing the polysiloxane's affinity and solubility in oil systems while increasing its water solubility. This not only improves defoaming and anti-foaming properties, but also imparts excellent heat resistance, acid and alkali resistance, anti-aging, electrical insulation, flexibility, non-toxicity and odorlessness, storage stability, and ease of use.

[0003] Current methods for linking polyether and polysiloxane segments are primarily Si-OC and Si-C. The Si-OC type is susceptible to hydrolysis and has poor chemical stability. The Si-C type exhibits better hydrolytic stability. However, the synthesis of Si-C polyether-modified polysiloxanes requires the use of expensive platinum catalysts, which increases costs. Furthermore, polyether-modified polysiloxanes inherently possess excellent defoaming properties. Therefore, they can be compounded with silicone pastes, polyether additives, and other additives to create self-emulsifying defoamers that are cost-effective, stable, and highly efficient. This self-emulsification property stems from the fact that when polyether-modified polysiloxanes are added to water, the hydrophobic polysiloxane segments curl internally while the hydrophilic polyether segments extend externally, forming micelles similar to an emulsion in the water. This facilitates uniform dispersion of the silicone-ether defoamer in the foaming solution. Polyether-modified polysiloxanes inherently possess excellent defoaming properties, but their use alone is costly. Compounding them with other additives and water not only improves their performance but also significantly reduces costs. Based on this, the present invention proposes a defoamer with rapid dispersion, a low cloud point, and resistance to high temperatures, high pressures, and strong acids and bases. Summary of the Invention

[0004] The object of the present invention is to provide a defoaming agent with fast dispersion speed, low cloud point, high temperature and high pressure resistance, and strong acid and alkali resistance.

[0005] In a first aspect, the present invention provides a defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, and strong acid and alkali resistance, which is prepared from the following components:

[0006] White carbon black silicone paste 5%-50%,

[0007] End-capped polyether modified polysiloxane 1%-25%,

[0008] Spherical polysilsesquioxane 0.1%-10%,

[0009] Complexing agent 1-25%,

[0010] Thickening agent 0.1-10%,

[0011] Sterilizing agent 0.05-0.5%,

[0012] The balance is water, and the sum of the weight percentages of the components is 100%.

[0013] Further, the preparation method of the white carbon black silicone paste comprises: adding hydrophobic fumed white carbon black into branched dimethyl silicone oil, heating and stirring for 25-35 min under the conditions of nitrogen inlet and a temperature of 120-140℃, and then adding a certain amount of dimethyl silicone oil to dilute the white carbon black to a mass fraction of 5%-10% to obtain the white carbon black silicone paste.

[0014] Further, the weight ratio of the branched dimethyl silicone oil and the hydrophobic fumed white carbon black is (230-240):(4-6).

[0015] Further, the molecular structure of the capped polyether modified polysiloxane is shown in Structural Formula 1: Structural Formula 1.

[0016] (1) Preparation of long-chain alkyl hydrogen-containing silicone oil: under the condition of concentrated sulfuric acid catalysis, alkyl-terminated double end caps and hydrogen-containing silicone oil are stirred, and the reaction is carried out at a temperature not higher than 60℃ for 3-5h, and then sodium bicarbonate is added to adjust the pH to neutral; vacuum filtration is carried out to obtain colorless transparent product; the reaction equation is as follows:

[0017] (2) Preparation of allyl-terminated polyether: in a closed environment, propylene alcohol, propylene oxide and ethylene oxide, and alkali catalyst and initiator propylene alcohol are replaced by nitrogen, and then dehydrated by bubbling at a temperature of 100-110℃, and then a part of propylene oxide is added, and then another part of propylene oxide is added after the reaction is stable; after the reaction is completed, the temperature is lowered, and then ethylene oxide is added, and then the reaction is matured, and then the pressure is not lowered, and then the reaction is degassed by bubbling, and then the temperature is lowered, and then the reaction is neutralized by adding glacial acetic acid, and then the reaction is stirred, and then the reaction is bleached by adding hydrogen peroxide, and then the product is detected after being etherized with n-butyl ether, and then the reaction is stirred by adding an antioxidant, and then the product is obtained after cooling and discharging, which is a light yellow allyl-terminated polyether;

[0018] (3) Preparation of capped polyether modified polysiloxane: hydrogen-containing silicone oil and allyl-terminated polyether are stirred and mixed in a closed environment, and then dehydrated by bubbling at a temperature of 100-110℃, and then dimethylbenzene and Pt catalyst are added, and then the reaction is carried out at a temperature of 75-85℃, and then the reaction is ended when the reactants gradually become transparent and the Si-H content no longer changes, and then the reaction is ended, and then dimethylbenzene and other low-boiling substances are removed by vacuum distillation to obtain capped polyether modified polysiloxane; the reaction equation is as follows:

[0019]

[0020] Further, the mass fraction of hydrogen in the hydrogen-containing silicone oil is 1.5%-1.6%.

[0021] Further, the weight ratio of the alkyl-terminated double end cap, the hydrogen-containing silicone oil, concentrated sulfuric acid and sodium bicarbonate is (400-470):(130-150):(40-48):(70-90).

[0022] Further, the Pt-based catalyst includes one of chloroplatinic acid, Speier catalyst and Karstedt's catalyst.

[0023] Further, the step of nitrogen replacement includes: first, drawing negative pressure to below-0.095MPa, then filling nitrogen to 0.05MPa, repeating 2-4 times.

[0024] Further, the weight ratio of the mixture of propylene alcohol, propylene oxide and ethylene oxide, the base catalyst, propylene alcohol, propylene oxide, ethylene oxide, glacial acetic acid, hydrogen peroxide and antioxidant is (90-110):(0.25-0.35):(90-96):(120-140):(74-82):(0.2-0.4):(0.4-0.6):(2.5-3.5); the weight ratio of propylene alcohol, propylene oxide and ethylene oxide is 1:1.4:1.1.

[0025] Further, the antioxidant is citric acid / sodium citrate, and w(citric acid / sodium citrate)=1%.

[0026] Further, the base catalyst includes potassium hydroxide or sodium hydroxide.

[0027] Further, the weight ratio of the hydrogen silicone oil, end-allyl polyether, xylene and catalyst is (560-600):(280-320):(250-350):(0.2-0.4).

[0028] Further, the complex polyether is composed of the allyl polyether with number average molecular weight of 1220 and n(EO):n(PO)=3:1 in the molecule and the allyl polyether with number average molecular weight of 800 and n(EO):n(PO)=1:4 in the molecule.

[0029] Further, the weight ratio of the allyl polyether with n(EO):n(PO)=3:1 in the molecule and the allyl polyether with n(EO):n(PO)=1:4 in the molecule is (1-2):(1-2).

[0030] Further, the thickening agent comprises a functional modified polyether neutralized by glacial acetic acid, wherein the molecular structure of the functional modified polyether is shown in the structural formula 2: Structural formula 2

[0031] The raw material for preparing the functional modified polyether comprises mixed long-chain alkyl glycidyl ether and common polyether with a molar ratio of 1:1.1-1.2; and further comprises aluminum isopropyl alcohol with an addition amount of 0.03-0.05% of the sum of the mass of the mixed long-chain alkyl glycidyl ether and the common polyether.

[0032] The raw material for preparing the mixed long-chain alkyl glycidyl ether comprises C 12-14 alcohol, epichlorohydrin, phase transfer catalyst and aqueous sodium hydroxide solution, wherein the molar ratio of the C 12-14 alcohol and the epichlorohydrin is 1:1.1-1.5; the addition amount of the phase transfer catalyst is 0.3-0.7% of the mass of the C 12-14 alcohol; the molar ratio of the C 12-14 alcohol and the aqueous sodium hydroxide solution is 1:1-1.5.

[0033] The raw material for preparing the common polyether comprises propylene alcohol, ethylene oxide and propylene oxide with a weight ratio of (250-280):(210-230):(56-60), and sodium hydroxide with a weight amount of 0.08% of the total mass of the propylene alcohol, the ethylene oxide and the propylene oxide.

[0034] Further, the phase transfer catalyst is tetrabutylammonium bromide; and the mass concentration of the aqueous sodium hydroxide solution is 14-16%.

[0035] Further, the preparation steps of the thickening agent comprise:

[0036] Preparation of mixed long-chain alkyl glycidyl ether: mixing C 12-14 alcohol, epichlorohydrin and phase transfer catalyst to perform ring-opening addition reaction to obtain an intermediate product; the epichlorohydrin is added in a dropwise manner, and the reaction temperature is controlled at 55-60℃;

[0037] The ring-opening reaction equation is as follows:

[0038] After the dropwise addition of the epichlorohydrin is completed, the intermediate product and the aqueous sodium hydroxide solution are mixed to perform ring-closing reaction to obtain the mixed long-chain alkyl glycidyl ether; the reaction temperature is controlled at 55-60℃; and after the dropwise addition of the aqueous sodium hydroxide solution is completed, the mixture is incubated for 2-4 h;

[0039] The ring-closing reaction equation is as follows:

[0040] (2) Preparation of ordinary polyether: propylene glycol is mixed with ethylene oxide and propylene oxide to prepare ordinary polyether under the catalysis of sodium hydroxide; after the dropwise addition of propylene oxide is completed, the reaction is aged for 2-3 h, and the reaction temperature is controlled at 110-120 DEG C;

[0041] (3) Preparation of functionally modified polyether: the mixed long-chain alkyl glycidyl ether prepared is mixed with ordinary polyether and aluminum isopropyl alcohol to react to obtain functionally modified polyether; the reaction time is controlled at 1-2 h, and the reaction temperature is controlled at 80-120 DEG C;

[0042] The reaction equation for preparing the functionally modified polyether is as follows:

[0043] (4) Preparation of water-soluble high-molecular thickening agent: the functionally modified polyether obtained is neutralized with glacial acetic acid to obtain a water-soluble high-molecular thickening agent.

[0044] Further, the dropwise addition time of the epichlorohydrin in step (1) is controlled at 1-4 h; the aqueous sodium hydroxide solution is added in a dropwise manner, and the dropwise addition time is controlled at 3-4 h.

[0045] Further, the propylene oxide and ethylene oxide in step (2) are added in a dropwise manner; the ethylene oxide is directly added without degassing, and the dropwise addition time is controlled at 1-4 h.

[0046] Further, the molar ratio of the glacial acetic acid and sodium hydroxide is 1-1.5:1.

[0047] Further, the sterilizing agent is potassium sorbate.

[0048] Further, the preparation steps of the defoaming agent include: white carbon black silicon paste, spherical poly silyl and end-capped polyether modified polysiloxane are stirred with a homogenizer to mix them thoroughly, then compounded polyether, thickening agent, sterilizing agent and water are added and stirred uniformly, and then the homogenizer is continuously and rapidly stirred for 25-35 min to obtain uniformly mixed polyether modified polysiloxane defoaming agent.

[0049] The beneficial effects of the present application are:

[0050] The defoaming agent prepared by compounding has greatly reduced economic cost compared with directly using polyether modified polysiloxane, and the defoaming agent prepared by compounding with thickening agent, sterilizing agent and other related additives and water has excellent properties such as fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong base resistance. DETAILED DESCRIPTION

[0051] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application. Embodiments

[0052] The present application provides a defoaming agent with fast dispersion, low turbidity, high temperature and pressure resistance, strong acid and alkali resistance, which is prepared from the following components:

[0053] White carbon black silicon paste 5%-50%,

[0054] End-capped polyether modified polysiloxane 1%-25%,

[0055] Spherical poly silesquioxane 0.1%-10%,

[0056] Compound polyether 1%-25%,

[0057] Thickening agent 0.1%-10%,

[0058] Sterilizing agent potassium sorbate 0.05%-0.5%,

[0059] The balance is water, and the sum of the weight percentages of the components is 100%.

[0060] More specifically, taking the preparation of 1 kg of product as an example, the preparation method of the defoaming agent with fast dispersion, low turbidity, high temperature and pressure resistance, strong acid and alkali resistance in the present embodiment includes:

[0061] The 250 g of prepared silicon paste, 50 g of spherical poly silesquioxane and 150 g of end-capped polyether modified polysiloxane are stirred with a homogenizer to mix them thoroughly, and then 50 g of compound polyether, 5 g of thickening agent, 5 g of sterilizing agent and 125 g of water are added and stirred uniformly, followed by continued rapid stirring with the homogenizer for 30 minutes to obtain a mixed uniform polyether modified polysiloxane defoaming agent.

[0062] The preparation method of the white carbon black silicon paste includes: adding 5 g of hydrophobic fumed white carbon black to 235 g of branched dimethyl silicone oil; heating and stirring at 130℃ in a reaction kettle with a stirrer and a thermometer under nitrogen for 30 minutes; and then adding a certain amount of dimethyl silicone oil to dilute the white carbon black to a mass fraction of 7% to obtain the white carbon black silicon paste.

[0063] In a further embodiment, the method for preparing the white carbon silicon paste comprises: adding hydrophobic fumed white carbon into branched dimethyl silicone oil, heating and stirring for 25-35 min under the condition of nitrogen flow and temperature of 120-140 ℃, then adding a certain amount of dimethyl silicone oil to dilute the white carbon to a mass fraction of 5%-10% to obtain the white carbon silicon paste. The weight ratio of the branched dimethyl silicone oil to the hydrophobic fumed white carbon is (230-240):(4-6).

[0064] The method for preparing the capped polyether-modified polysiloxane comprises:

[0065] The method for preparing the long-chain alkyl-containing silicone oil is as follows:

[0066] In a 500 mL four-necked flask equipped with an electric stirrer, a thermometer, and a reflux condenser, 435 g of alkyl-capped double end-capped and 145 g of hydrogen-containing silicone oil with a hydrogen mass fraction of 1.5% are added, and 44 g of concentrated sulfuric acid is added as a catalyst. The stirring is started and the reaction is carried out, ensuring that the temperature in the bottle does not exceed 60 ℃ throughout the process. After 5 h of reaction, the temperature is reduced to room temperature, and 80 g of sodium bicarbonate is slowly added for neutralization, adjusting the pH to neutral.

[0067] Then, vacuum filtration is performed using a vacuum pump, and the obtained filtrate is subjected to negative pressure with a pressure less than -0.095 MPa to remove unreacted raw materials and small molecules, and the obtained product is a colorless transparent liquid.

[0068] The mass ratio of the alkyl-capped double end-capped to the hydrogen-containing silicone oil is 3:1.

[0069] The equation for preparing the hydrogen-containing silicone oil is as follows:

[0070] The method for preparing the n-butyl etherified single-end allyl-containing copolyether of ethylene oxide and propylene oxide is as follows:

[0071] The reaction raw materials are a mixture of propylene alcohol, propylene oxide, and ethylene oxide with a total weight of 100, and the weight ratio of propylene alcohol, propylene oxide, and ethylene oxide is 1:1.4:1.1.

[0072] After the end of the test leakage of the reactor, 0.3 g of sodium hydroxide as catalyst and 93 g of propenyl alcohol as initiator were added into the high-pressure reactor, the reactor was closed, the stirring was started, and the nitrogen was replaced for three times, first vacuumed to -0.095 MPa, then filled with nitrogen to 0.05 MPa, repeated for three times, after the replacement, vacuumed to -0.095 MPa, heated to 105 ℃, and dehydrated by bubbling for 1 hour, during which the water was vacuumed out while the nitrogen was slowly bubbled to ensure the pressure was less than -0.095 MPa; then 30 g of propylene oxide (PO) was added into the reactor, after the reaction was stable, the remaining 100 g of PO was slowly added, and the reaction temperature was maintained at 115 ℃;

[0073] After the PO reaction was completed, the temperature was lowered to 107 ℃, and 78 g of ethylene oxide (EO) was added, and the reaction temperature was maintained at 115 ℃; after the addition was completed, the reactor was incubated for 10 min, and then the temperature was lowered to 70 ℃ or below, and the nitrogen was pressurized to normal pressure, then 0.3 g of glacial acetic acid was added for neutralization, and after stirring for 10 min, 0.5 g of hydrogen peroxide was added for decolorization, and after n-butyl etherization, the product acid value was detected, and the nitrogen blowing was stopped when the product acid value was less than 0.4 mgKOH / g; then 3 g of a mixture of citric acid / sodium citrate was used as an antioxidant for antioxidant treatment, and the amount was w(citric acid / sodium citrate)=1%, and the reaction was carried out at 80 ℃ for 1 hour, during which the nitrogen was blown; finally, the product was cooled and discharged; the color of the terminal allyl polyether was light yellow;

[0074] (3) The preparation method of the capped polyether modified polysiloxane is as follows:

[0075] After the test leakage was completed, 580 g of low hydrogen-containing silicone oil and 300 g of terminal allyl polyether were weighed, and the polyether was in excess, and then they were added into the reactor, the reactor was closed, the stirring was started, and the nitrogen was replaced for three times, first vacuumed to -0.095 MPa, then filled with nitrogen to 0.05 MPa, repeated for three times, after the replacement, vacuumed to 0.095 MPa, heated to 105 ℃, and dehydrated by bubbling for 1 hour, during which the water was vacuumed out while the nitrogen was slowly bubbled to ensure the pressure was less than -0.095 MPa. Then 300 g of solvent dimethylbenzene was added, after the solution in the bottle was uniformly mixed, the temperature was raised to 60 ℃, and 0.3 g of Speier catalyst was added, after the induction period, the reaction was exothermic and the temperature was increased by 15 ℃; the reaction was incubated at 80 ℃, and as the reaction proceeded, the reactants gradually became transparent; the Si-H content of the reactants was determined, and when the Si-H content did not change, the reaction endpoint was determined; after the reaction was completed, the dimethylbenzene and other low-boiling substances were removed by vacuum distillation, and the capped polyether modified polysiloxane was obtained. The reaction equation is as follows:

[0076] The complex polyether is composed of allyl polyether with number average molecular weight of 1220 and n(EO):n(PO)=3:1 in the molecule and allyl polyether with number average molecular weight of 800 and n(EO):n(PO)=1:4 in the molecule in a weight ratio of 1:1

[0077] The preparation method of the thickening agent comprises the following steps:

[0078] (1) preparing mixed long carbon chain alkyl glycidyl ether:

[0079] The intermediate product is obtained by mixing 315 g of C 12-14 alcohol, 98 g of epichlorohydrin and 1.575 g of phase transfer catalyst tetrabutylammonium bromide for ring-opening addition reaction; the epichlorohydrin is added dropwise, the dropwise adding time is controlled to be 3 h, and the reaction temperature is controlled to be 57°C; after the dropwise adding of the epichlorohydrin is completed, the temperature is kept for 3 h for curing;

[0080] The ring-opening reaction equation is as follows:

[0081] In a further embodiment, the molar ratio of the C 12-14 alcohol and the epichlorohydrin is 1:1.1-1.5; and the addition amount of the phase transfer catalyst is 0.3-0.7% of the mass of the C 12-14 alcohol;

[0082] The mixed long carbon chain alkyl glycidyl ether is obtained by mixing 414 g of the intermediate product and 300 g of 15% sodium hydroxide aqueous solution in mass concentration for ring-closing reaction; the sodium hydroxide aqueous solution is added dropwise, the dropwise adding time is controlled to be 3.5 h, and the reaction temperature is controlled to be 57°C; after the dropwise adding of the sodium hydroxide aqueous solution is completed, the temperature is kept for 3 h for curing;

[0083] The ring-closing reaction equation is as follows:

[0084] In a further embodiment, the molar ratio of the C 12-14 alcohol and the sodium hydroxide aqueous solution is 1:1-1.5; and the mass concentration of the sodium hydroxide aqueous solution is 14-16%.

[0085] (2) preparing ordinary polyether:

[0086] The common polyether is prepared by mixing 265 g of allyl alcohol with 222 g of ethylene oxide and 58 g of propylene oxide under the catalysis of 0.436 g of sodium hydroxide; the propylene oxide and the ethylene oxide are added dropwise, the propylene oxide is kept for 2.5 h after the dropwise addition is completed, the ethylene oxide is directly added dropwise without degassing, the dropwise addition time is controlled to be 3 h, and the reaction temperature is controlled to be 115°C;

[0087] The addition amount of the sodium hydroxide is 0.08% of the total mass of the allyl alcohol, the propylene oxide and the ethylene oxide.

[0088] (3) Preparation of the functionally modified polyether:

[0089] The functionally modified polyether is prepared by mixing 455 g of the prepared mixed long-chain alkyl glycidyl ether with 545 g of the common polyether and 0.3 g of aluminum isopropoxide; the reaction time is controlled to be 1.5 h, and the reaction temperature is controlled to be 100°C.

[0090] The reaction equation for preparing the functionally modified polyether is as follows:

[0091] In a further example, the molar ratio of the mixed long-chain alkyl glycidyl ether to the common polyether is 1:1.15; the addition amount of the aluminum isopropoxide is 0.04% of the total mass of the mixed long-chain alkyl glycidyl ether and the common polyether.

[0092] (4) Preparation of the water-soluble high-molecular thickening agent:

[0093] The functionally modified polyether is neutralized by 0.5 g of glacial acetic acid to obtain the water-soluble high-molecular thickening agent.

[0094] In a further example, the molar ratio of the glacial acetic acid to the sodium hydroxide is 1-1.5:1.

[0095] Performance test method:

[0096] 1. Defoaming and foam suppressing performance test method:

[0097] The compounded defoaming agent, a commercially available silicone defoaming agent sample and a polyether defoaming agent sample are tested for defoaming performance in the following high-temperature, strong-acid and alkaline foaming liquids:

[0098] A 0.5% sodium dodecyl benzene sulfonate aqueous solution is adjusted to a pH of 13.0 by an alkali solution and heated to 85°C as a foaming liquid A, and a same volume and same mass concentration of the sodium dodecyl benzene sulfonate aqueous solution is adjusted to a pH of 2.0 by an acid and heated to 85°C as a foaming liquid B. The selected defoaming agents are tested for defoaming performance by a Ross foam meter, and the addition amount of the three defoaming agents is selected to be 100*10 -6The defoaming, bubble suppressing time, and the defoaming performance under high temperature and strong acid and alkali conditions of the defoaming agent were recorded, and the test results are shown in Table 1 below.

[0099] Table 1

[0100]

[0101] Stability test method of the defoaming agent:

[0102] The stability test of the defoaming agent mainly includes the following five kinds:

[0103] (1) Centrifugal stability: 5 ml of the defoaming agent sample was centrifuged at 3000 r / min for 30 min on a centrifuge, and whether it was stable was observed.

[0104] (2) Thermal stability: 2 g of the defoaming agent sample was placed in a small test tube, sealed with a rubber plug, and heated in a 120 ℃ oil bath. After cooling to room temperature, whether it was stable was observed.

[0105] (3) Low temperature stability: 2 g of the defoaming agent sample was placed in a small test tube, sealed with a rubber plug, and frozen at-10 ℃. After natural thawing, whether it was stable was observed.

[0106] (4) Storage stability: 50 ml of the defoaming agent sample was placed at room temperature for one week, and whether it was stable was observed.

[0107] (5) Dilution stability: 5 g of the defoaming agent sample was diluted with water to form a 10% water dispersion, and after being placed for 24 h, whether there was oil floating was observed.

[0108] The comparison results of the stability of the defoaming agent are shown in Table 2 below:

[0109] Table 2

[0110]

[0111] Finally, it should be noted that the above examples are only used to illustrate the technical solutions described in the present application and do not limit the technical solutions described in the present application; those skilled in the art should understand that the present application can still be modified or replaced by equivalents; and all technical solutions and improvements that do not deviate from the spirit and scope of the present application should be covered in the scope of the claims of the present application.

Claims

1. A defoaming agent with fast dispersion, low cloud point, high temperature and pressure resistance, strong acid and strong base resistance, characterized in that, Prepared from the following components: White carbon black silicone paste 5%-50%, End-capped polyether modified polysiloxane 1%-25%, Spherical polysilsesquioxane 0.1%-10%, Compound polyether 1%-25%, Thickening agent 0.1%-10%, Sterilizing agent 0.05%-0.5%, The balance is water, the sum of the weight percentages of the components is 100%; The molecular structure of the end-capped polyether modified polysiloxane is shown in structural formula 1: Structure 1; The compound polyether is composed of allyl polyether with a number average molecular weight of 1220 and n(EO):n(PO)=3:1 in the molecule, and allyl polyether with a number average molecular weight of 800 and n(EO):n(PO)=1:4 in the molecule.

2. The defoamer according to claim 1, characterized in that, The preparation method of the white carbon black silicone paste comprises: adding hydrophobic fumed white carbon black to branched dimethyl silicone oil, heating and stirring under the conditions of nitrogen inlet and temperature of 120-140℃ for 25-35min, and then adding a certain amount of dimethyl silicone oil to dilute to a mass fraction of 5%-10% of the white carbon black, to obtain the white carbon black silicone paste.

3. The defoamer according to claim 2, characterized in that, The weight ratio of the branched dimethyl silicone oil to the hydrophobic fumed white carbon black is (230-240):(4-6).

4. The defoamer according to claim 1, characterized in that, The weight ratio of the allyl polyether with n(EO):n(PO)=3:1 in the molecule to the allyl polyether with n(EO):n(PO)=1:4 in the molecule is (1-2):(1-2).

5. The defoamer according to claim 1, characterized in that, The thickening agent comprises a functional modified polyether neutralized with glacial acetic acid, wherein the molecular structure of the functional modified polyether is shown in structural formula 2: Structural formula 2; The raw materials for preparing the functional modified polyether comprise mixed long-chain alkyl glycidyl ether and ordinary polyether with a molar ratio of 1:1.1-1.2; and further comprise 0.03-0.05% of isopropyl aluminum alcohol based on the total mass of the mixed long-chain alkyl glycidyl ether and the ordinary polyether; The raw materials for preparing the mixed long-chain alkyl glycidyl ether include C 12-14 Alcohol, epichlorohydrin, phase transfer catalyst and sodium hydroxide aqueous solution, wherein C 12-14 The molar ratio of alcohol to epichlorohydrin is 1:1.1-1.5; the amount of phase transfer catalyst added is the C 12-14 0.3-0.7% of alcohol mass; C 12-14 The molar ratio of alcohol to sodium hydroxide aqueous solution is 1:1-1.5; The raw materials for preparing the ordinary polyether comprise propylene alcohol, ethylene oxide and propylene oxide with a weight ratio of (250-280):(210-230):(56-60), and 0.08% of sodium hydroxide based on the total mass of the propylene alcohol, the ethylene oxide and the propylene oxide.

6. The defoamer according to claim 5, characterized in that, The phase transfer catalyst is tetrabutylammonium bromide; and the mass concentration of the sodium hydroxide aqueous solution is 14-16%.

7. The defoamer according to claim 1, characterized in that, The sterilizing agent is potassium sorbate.

8. The defoamer according to claim 1, characterized in that, The preparation steps of the defoaming agent comprise: stirring the white carbon black silicone paste, the spherical polysilsesquioxane and the end-capped polyether modified polysiloxane with a homogenizer to fully mix them, then adding the compound polyether, the thickening agent, the sterilizing agent and water to stir them uniformly, and continuing to stir them quickly with the homogenizer for 25-35min to obtain the mixed polyether modified polysiloxane defoaming agent.

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