Defoaming agent with characteristics of rapid dispersion, low cloud point, high temperature resistance, high pressure resistance, strong acid resistance and strong alkali resistance

Abstract

The invention relates to a defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance, which is prepared from the following components in percentage by weight: 5%-50% of white carbon black silicon paste, 1%-25% of terminated polyether modified polysiloxane, 0.1%-10% of spherical polysilsesquioxane, 1%-25% of compound polyether, 0.1%-10% of thickening agent, 0.05%-0.5% of sterilizing agent and the balance of water, and the sum of the weight percentages of the components is 100%. The invention also provides a production process of the defoaming agent, which comprises the following steps of: stirring the white carbon black silicon paste, the spherical polysilsesquioxane and the terminated polyether modified polysiloxane by using a homogenizer to be fully mixed, then adding the compound polyether, the thickening agent and the sterilizing agent, uniformly stirring, and continuously and quickly stirring for 25-35 minutes by using the homogenizer to obtain the defoaming agent. The uniformly mixed polyether modified polysiloxane defoaming agent is obtained. The invention aims to provide the defoaming agent which is high in dispersion speed, low in cloud point, resistant to high temperature and high pressure and resistant to strong acid and strong alkali.

Description

Technical Field

[0001] The invention relates to the technical field of defoamers, and in particular to a defoamer 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 polysiloxane has become a hot spot for research and development at home and abroad. Through polyether grafting or block modification, the synergistic properties of the two components are brought into play. The hydrophilic polyether segment gives it self-emulsification, and the hydrophobic polysiloxane segment gives it low surface tension, reducing the affinity and solubility of polysiloxane in the oil system and increasing its water solubility, which not only improves the defoaming and anti-foaming properties, but also gives it excellent heat resistance, acid and alkali resistance, anti-aging, electrical insulation, softness, non-toxicity and tastelessness, storage stability and easy use.

[0003] The current connection modes of polyether segments and polysiloxane segments are mainly divided into Si-OC type and Si-C type. Among them, Si-OC type is easy to hydrolyze and has poor chemical stability. Si-C type has better hydrolysis stability, but the synthesis of Si-C type polyether-modified polysiloxane requires the use of expensive platinum as a catalyst, which increases the economic cost. In addition, polyether-modified polysiloxane itself has good defoaming performance, so polyether-modified polysiloxane can be compounded with silicone paste, polyether and other additives to obtain a self-emulsifying defoamer with low cost, stable performance and higher efficiency. It is called self-emulsification because after adding polyether-modified polysiloxane to water, the hydrophobic polysiloxane segment in its molecule will curl inside and the hydrophilic polyether segment will stretch outside, thereby forming micelles similar to the emulsified state in water, which helps the silicone ether defoamer to be evenly dispersed in the foaming liquid. Polyether-modified polysiloxane itself has good defoaming performance, but the cost of using it alone is high. Compounding it with other additives and water can not only improve its performance, but also greatly reduce the economic cost. Based on this, the present invention proposes a defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance. Summary of the invention

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

[0005] In the first aspect, the present invention provides a defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance, which is 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%, Thickener 0.1%-10%, Sterilizer 0.05%-0.5%, The balance is water, and the sum of the weight percentages of the various components is 100%.

[0006] Furthermore, the preparation method of the silica paste includes: adding hydrophobic fumed silica to branched dimethyl silicone oil, heating and stirring for 25-35 minutes under the conditions of nitrogen and a temperature of 120-140°C, and after mixing evenly, adding a certain amount of dimethyl silicone oil to dilute to a silica mass fraction of 5%-10%, thereby obtaining silica paste.

[0007] Furthermore, the weight ratio of the branched dimethyl silicone oil to the hydrophobic fumed silica is (230-240):(4-6).

[0008] Furthermore, the molecular structure of the end-capped polyether-modified polysiloxane is shown in Structural Formula 1: Structural formula 1.

[0009] (1) Preparation of long-chain alkyl hydrogenated silicone oil: Stir the alkyl-terminated double-capped silicone oil with hydrogenated silicone oil under the catalytic condition of concentrated sulfuric acid, react for 3-5 hours at a temperature not higher than 60°C, add sodium bicarbonate to adjust the pH to neutral; vacuum filter to obtain a colorless and transparent product; the reaction equation is as follows:

[0010] (2) Preparation of terminal allyl polyether: Propylene alcohol, propylene oxide, ethylene oxide, alkali catalyst and initiator propenyl alcohol are replaced with nitrogen in a closed environment, and bubbling dehydration is carried out at a temperature of 100-110°C, and then a portion of propylene oxide is added, and another portion of propylene oxide is added after the reaction is stable; after the reaction is complete, the temperature is lowered, ethylene oxide is added, and the reaction is kept warm for aging. After the pressure stops decreasing, bubbling degassing is carried out, and glacial acetic acid is added to neutralize when the temperature is lowered and the pressure is normal, and hydrogen peroxide is added after stirring for decolorization, and the acid value of the product is detected after n-butyl etherification, and then an antioxidant is added to stir the reaction, and the material is cooled to obtain a light yellow terminal allyl polyether; (3) Preparation of end-capped polyether-modified polysiloxane: Stir and mix hydrogen-containing silicone oil and terminal allyl polyether in a closed environment, replace with nitrogen, and dehydrate by bubbling at a temperature of 100-110°C, then add xylene and Pt-based catalyst, and keep the temperature at 75-85°C for reaction. As the reactants gradually become transparent, the Si-H content no longer changes. After the reaction is completed, vacuum distillation is performed to remove xylene and other low-boiling substances to obtain end-capped polyether-modified polysiloxane. The reaction equation is as follows:

[0011] Furthermore, the mass fraction of hydrogen in the hydrogen-containing silicone oil is 1.5%-1.6%.

[0012] Furthermore, the weight ratio of the alkyl-terminated double cap, hydrogen-containing silicone oil, concentrated sulfuric acid and sodium bicarbonate is (400-470): (130-150): (40-48): (70-90).

[0013] Furthermore, the Pt-based catalyst includes one of chloroplatinic acid, Speier catalyst, and Karstedt's catalyst.

[0014] Furthermore, the nitrogen replacement step includes: firstly pumping the negative pressure to below -0.095MPa, then filling with nitrogen to 0.05MPa, and repeating 2-4 times.

[0015] Furthermore, 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.

[0016] Furthermore, the antioxidant is citric acid / sodium citrate, and w(citric acid / sodium citrate)=1%.

[0017] Furthermore, the alkaline catalyst includes potassium hydroxide or sodium hydroxide.

[0018] Furthermore, the weight ratio of the hydrogen silicone oil, terminal allyl polyether, xylene and catalyst is (560-600): (280-320): (250-350): (0.2-0.4).

[0019] Furthermore, the compound polyether is composed of an allyl polyether with a number average molecular weight of 1220 and n(EO):n(PO)=3:1 in the molecule and an allyl polyether with a number average molecular weight of 800 and n(EO):n(PO)=1:4 in the molecule.

[0020] Furthermore, the weight ratio of the allyl polyether in which n(EO):n(PO)=3:1 in the molecule to the allyl polyether in which n(EO):n(PO)=1:4 in the molecule is (1-2):(1-2).

[0021] Furthermore, the thickener is obtained by neutralizing a functional modified polyether with glacial acetic acid, wherein the molecular structure of the functional modified polyether is shown in Structural Formula 2: Structural formula 2; The functional modified polyether preparation raw material includes a mixed long-chain alkyl glycidyl ether and a common polyether in a molar ratio of 1:1.1-1.2; and also includes 0.03-0.05% of aluminum isopropoxide added in an amount equal to the sum of the mass of the mixed long-chain alkyl glycidyl ether and the common polyether; The raw materials for preparing the mixed long-chain alkyl glycidyl ether include C 12-14 alcohol, epichlorohydrin, a phase transfer catalyst and an aqueous sodium hydroxide 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 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 common polyether include propylene alcohol, ethylene oxide and propylene oxide in a weight ratio of (250-280): (210-230): (56-60), and sodium hydroxide in a weight percentage of 0.08% of the total weight of propylene alcohol, propylene oxide and ethylene oxide.

[0022] Furthermore, the phase transfer catalyst is tetrabutylammonium bromide; and the mass concentration of the sodium hydroxide aqueous solution is 14-16%.

[0023] Furthermore, the preparation steps of the thickener include: Preparation of mixed long carbon chain alkyl glycidyl ethers: C 12-14 Alcohol, epichlorohydrin and a phase transfer catalyst are mixed to undergo a ring-opening addition reaction to obtain an intermediate product; epichlorohydrin is added dropwise, and the reaction temperature is controlled at 55-60°C; The ring-opening reaction equation is as follows:

[0024] After the epichlorohydrin is added dropwise, the mixture is kept warm and aged for 2-4 hours; the intermediate product is mixed with a sodium hydroxide aqueous solution for a ring-closing reaction to obtain a mixed long-chain alkyl glycidyl ether; the reaction temperature is controlled at 55-60° C.; after the sodium hydroxide aqueous solution is added dropwise, the mixture is kept warm and aged for 2-4 hours; The closed-loop reaction equation is as follows:

[0025] (2) Preparation of ordinary polyether: Propylene alcohol is mixed with ethylene oxide and propylene oxide, and ordinary polyether is obtained under the catalysis of sodium hydroxide; after the propylene oxide is added dropwise, the mixture is kept warm and aged for 2-3 hours, and the reaction temperature is controlled at 110-120°C; (3) Preparation of functional modified polyether: The prepared mixed long-chain alkyl glycidyl ether is mixed with common polyether and aluminum isopropoxide to react to obtain functional modified polyether; the reaction time is controlled within 1-2 h, and the reaction temperature is controlled within 80-120°C; The reaction equation for preparing functional modified polyether is as follows:

[0026] (4) Preparation of a water-soluble polymer thickener: The obtained functionally modified polyether is added to glacial acetic acid for neutralization to obtain a water-soluble polymer thickener.

[0027] Furthermore, in the step (1), the epichlorohydrin is added dropwise for a time period of 1-4 h; the sodium hydroxide aqueous solution is added dropwise for a time period of 3-4 h.

[0028] Furthermore, in the step (2), propylene oxide and ethylene oxide are added dropwise; ethylene oxide is added dropwise directly without degassing, and the addition time is controlled within 1-4 h.

[0029] Furthermore, the molar ratio of the glacial acetic acid to the sodium hydroxide is 1-1.5:1.

[0030] Furthermore, the sterilizing agent is potassium sorbate.

[0031] Furthermore, the preparation step of the defoamer includes: stirring the white carbon black silicone paste, spherical polysilsesquioxane and blocked polyether modified polysiloxane with a homogenizer to fully mix them, then adding the compounded polyether, thickener, sterilizer and water to stir evenly, and then continuing to stir quickly with the homogenizer for 25-35 minutes to obtain a uniformly mixed polyether modified polysiloxane defoamer.

[0032] The beneficial effects of the present invention are: The defoamer prepared by the compounding of the present invention greatly reduces the economic cost compared with directly using polyether modified polysiloxane, and the defoamer prepared by compounding with relevant auxiliary agents such as thickeners and sterilizers and water has excellent properties of fast dispersion, low cloud point, high temperature and high pressure resistance, and strong acid and alkali resistance. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0034] The present invention provides a defoamer with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance, which is 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%, Thickener 0.1%-10%, Sterilizer potassium sorbate 0.05%-0.5%, The balance is water, and the sum of the weight percentages of the various components is 100%.

[0035] More specifically, taking the preparation of 1 kg of product as an example, the preparation method of a defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali in this embodiment includes: 250 g of the prepared silicone paste, 50 g of spherical polysilsesquioxane and 150 g of blocked polyether modified polysiloxane were stirred with a homogenizer to be fully mixed, and then 50 g of compound polyether, 5 g of thickener, 5 g of sterilizer and 125 g of water were added and stirred evenly, and then continued to stir rapidly with a homogenizer for 30 minutes to obtain a uniformly mixed polyether modified polysiloxane defoamer.

[0036] The preparation method of the silica paste comprises: adding 5 g of hydrophobic fumed silica to 235 g of branched dimethyl silicone oil; heating and stirring at 130° C. for 30 minutes in a reactor with a stirrer and a thermometer and nitrogen gas; adding a certain amount of dimethyl silicone oil to dilute the mixture to a mass fraction of 7% to obtain silica paste after the mixture is evenly mixed; In a further embodiment, the preparation method of the silica paste includes: adding hydrophobic fumed silica to branched dimethyl silicone oil, heating and stirring for 25-35 minutes under the conditions of nitrogen gas and temperature of 120-140°C, and then adding a certain amount of dimethyl silicone oil to dilute the mixture to a mass fraction of 5%-10% of the silica to obtain the silica paste. The weight ratio of the branched dimethyl silicone oil to the hydrophobic fumed silica is (230-240): (4-6).

[0037] Wherein, the preparation method of the end-capped polyether-modified polysiloxane comprises: (1) The preparation method of long-chain alkyl hydrogen-containing silicone oil is as follows: In a 500 mL four-necked flask equipped with an electric stirrer, a thermometer, and a reflux condenser, add 435 g of alkyl-terminated double-capped and 145 g of hydrogen-containing silicone oil with a hydrogen mass fraction of 1.5%, and then add 44 g of concentrated sulfuric acid as a catalyst. Start stirring to react. Ensure that the temperature in the flask is not higher than 60 °C during the whole process. After reacting for 5 h and cooling to room temperature, slowly add 80 g of sodium bicarbonate to neutralize and adjust the pH to neutral.

[0038] A vacuum pump is then used for filtration to reduce the negative pressure of the filtrate to less than -0.095 MPa, thereby removing unreacted raw materials and small molecules, and the product obtained is a colorless and transparent liquid. Among them, the mass ratio of the alkyl-terminated double head and the hydrogen-containing silicone oil is 3:1.

[0039] The formula for preparing hydrogenated silicone oil is as follows:

[0040] (2) The preparation method of the n-butyl etherified single-end allyl ethylene oxide and propylene oxide copolyether is as follows: The reaction raw material is a mixture of propylene alcohol, propylene oxide and ethylene oxide with a total weight of 100, wherein the weight ratio of propylene alcohol, propylene oxide and ethylene oxide is 1:1.4:1.1; After the reactor leak test, add 0.3% of the total mass of the raw materials, sodium hydroxide (0.3 g), an alkaline catalyst, and 93 g of initiator propylene alcohol into the autoclave, seal the autoclave, start stirring, and replace with nitrogen three times. First, pump the negative pressure to below -0.095 MPa, then fill with nitrogen to 0.05 MPa, repeat three times, and after the replacement, evacuate to below -0.095 MPa, heat to 105 °C, and bubbling dehydration for 1 hour. Specifically, bubbling nitrogen slowly while vacuuming water to ensure that the pressure is less than -0.095 MPa; then press about 30 g of PO into the propylene oxide (PO) storage tank, and slowly add the remaining 100 g of PO after the reaction is stable, and the reaction temperature is maintained between 115 °C; After the PO reaction is complete, the temperature is lowered to 107 °C, and 78 g of ethylene oxide (EO) is added, and the reaction temperature is maintained at 115 °C; after the addition is completed, the reaction is kept warm and aged until the pressure in the kettle returns to -0.1 MPa. After the pressure stops decreasing, nitrogen bubbling is used for degassing for 10 minutes; after the degassing is completed, the temperature is lowered to below 70 °C, nitrogen is pressurized to normal pressure, and then 0.3 g of glacial acetic acid is added for neutralization. After stirring for 10 minutes, 0.5 g of hydrogen peroxide is added for decolorization. After n-butyl etherification, the acid value of the product is detected, and nitrogen is blown until the acid value of the product is less than 0.4 mgKOH / g, and the blowing is stopped; then 3 g of citric acid / sodium citrate compound is used as an antioxidant for antioxidant treatment, and the dosage is w (citric acid / sodium citrate) = 1%, and the reaction is carried out at 80 °C for 1 hour under stirring. During this process, nitrogen is kept blowing; finally, the material is cooled and discharged; the color of the terminal allyl polyether is light yellow; (3) The preparation method of the end-capped polyether-modified polysiloxane is as follows: After the leak test, weigh 580 g of raw material low-hydrogen silicone oil and 300 g of terminal allyl polyether, of which the polyether is in excess, and put them into the reactor together. Close the reactor, start stirring, and replace with nitrogen three times. Specifically, first evacuate the negative pressure to below -0.095 MPa, then fill with nitrogen to 0.05 MPa, and repeat three times. After the replacement is completed, evacuate to below 0.095 MPa, raise the temperature to 105 ℃, and dehydrate by bubbling for 1 hour. Specifically, vacuum pump water while slowly bubbling with nitrogen to ensure that the pressure is less than -0.095 MPa. Then add 300 g of solvent xylene, and after the solution in the bottle is evenly mixed, heat it to 60 °C and add 0.3 g of Speier catalyst. After the induction period, the reaction releases heat and produces a temperature rise of 15 °C; keep the reaction at 80 °C, and the reactant gradually becomes transparent as the reaction proceeds; track and measure the Si-H content of the reactant, and determine the reaction end point when the Si-H content no longer changes; after the reaction is completed, vacuum distillation is used to remove xylene and other low-boiling substances to obtain end-capped polyether-modified polysiloxane. The reaction equation is as follows:

[0041] The compound polyether is composed of an allyl polyether having a number average molecular weight of 1220 and n(EO):n(PO)=3:1 in the molecule and an allyl polyether having a number average molecular weight of 800 and n(EO):n(PO)=1:4 in the molecule in a weight ratio of 1:1. Wherein, the preparation method of the thickener comprises: (1) Preparation of mixed long carbon chain alkyl glycidyl ethers: 315 g C 12-14 Alcohol, 98 g of epichlorohydrin and 1.575 g of tetrabutylammonium bromide as a phase transfer catalyst were mixed for ring-opening addition reaction to obtain an intermediate product; epichlorohydrin was added dropwise, the addition time was controlled at 3 h, and the reaction temperature was controlled at 57 ° C; after the epichlorohydrin was added dropwise, the mixture was kept warm for 3 h; The ring-opening reaction equation is as follows:

[0042] In a further embodiment, C 12-14 The molar ratio of alcohol to epichlorohydrin is 1:1.1-1.5; the amount of phase transfer catalyst added is 12-14 0.3-0.7% of alcohol mass; 414 g of the intermediate product and 300 g of a sodium hydroxide aqueous solution with a mass concentration of 15% were mixed for a ring-closing reaction to obtain a mixed long-chain alkyl glycidyl ether; the sodium hydroxide aqueous solution was added dropwise, the addition time was controlled at 3.5 h, and the reaction temperature was controlled at 57°C; after the sodium hydroxide aqueous solution was added dropwise, the mixture was kept warm for 3 h; The closed-loop reaction equation is as follows:

[0043] In a further embodiment, C 12-14 The molar ratio of alcohol to sodium hydroxide aqueous solution is 1:1-1.5; the mass concentration of sodium hydroxide aqueous solution is 14-16%.

[0044] (2) Preparation of ordinary polyether: 265 g of propylene alcohol, 222 g of ethylene oxide and 58 g of propylene oxide were mixed, and ordinary polyether was prepared under the catalysis of 0.436 g of sodium hydroxide; propylene oxide and ethylene oxide were added by dropwise addition, and after the addition of propylene oxide was completed, the mixture was kept warm and aged for 2.5 h, and ethylene oxide was directly added dropwise without degassing, and the addition time was controlled at 3 h, and the reaction temperature was controlled at 115°C; The added amount of sodium hydroxide is 0.08% of the total mass of propylene alcohol, propylene oxide and ethylene oxide.

[0045] (3) Preparation of functional modified polyether: 455 g of the obtained mixed long-chain alkyl glycidyl ether was mixed with 545 g of common polyether and 0.3 g of aluminum isopropoxide to react to obtain functional modified polyether; the reaction time was controlled at 1.5 h and the reaction temperature was controlled at 100°C; The reaction equation for preparing functional modified polyether is as follows:

[0046] In a further embodiment, the molar ratio of the mixed long-chain alkyl glycidyl ether to the common polyether is 1:1.15; the amount of aluminum isopropoxide added is 0.04% of the sum of the mass of the mixed long-chain alkyl glycidyl ether and the common polyether; (4) Preparation of water-soluble polymer thickener: The obtained functionally modified polyether was neutralized by adding 0.5 g of glacial acetic acid to obtain a water-soluble polymer thickener.

[0047] In a further embodiment, the molar ratio of glacial acetic acid to sodium hydroxide is 1-1.5:1.

[0048] Performance testing method: 1. Defoaming and antifoaming performance test method: The defoaming performance of the compounded defoamer, commercially available silicone defoamer samples and polyether defoamer samples were tested in the following high temperature, strong acid and alkaline foaming liquids: The sodium dodecylbenzene sulfonate aqueous solution with a mass concentration of 0.5% was adjusted to a pH of 13.0 with alkali solution and heated to 85°C as foaming liquid A. The sodium dodecylbenzene sulfonate aqueous solution with the same volume and mass concentration was adjusted to a pH of 2.0 with acid and heated to 85°C as foaming liquid B. The defoaming performance of the selected defoamers was tested using a Roche foam instrument. The addition amount of the three defoamers was selected to be 100*10 -6 , record the defoaming and anti-foaming time, and the defoaming performance test results under high temperature and strong acid and alkali conditions are shown in Table 1 below: Table 1

[0049] Stability performance test method: The stability performance tests of defoamers mainly include the following five types: (1) Centrifugal stability: Take 5 ml of the defoamer sample and centrifuge it at 3000 r / min for 30 min to observe whether it is stable.

[0050] (2) Thermal stability: Place 2 g of the foaming agent sample into a small test tube, plug it with a rubber stopper, and heat it in a 120°C oil bath. Take it out and cool it to room temperature, and observe whether it is stable.

[0051] (3) Low temperature stability: Place 2 g of the foam sample into a small test tube, plug it with a rubber stopper, and freeze it at -10°C. Take it out and thaw it naturally to observe whether it is stable.

[0052] (4) Storage stability: Take 50 ml of the defoamer sample and place it at room temperature for one week to observe whether it is stable.

[0053] (5) Dilution stability: Take 5 g of defoamer sample and dilute it with water to make a 10% aqueous dispersion. After leaving it for 24 hours, visually inspect whether there is floating oil.

[0054] The comparison results of the stability performance of the defoaming agent are shown in Table 2 below: Table 2

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A defoamer with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali 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%, Thickener 0.1%-10%, Sterilizer 0.05%-0.5%, The balance is water, and the sum of the weight percentages of the various components is 100%.

2. The defoamer according to claim 1, which has fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance, is characterized in that: The preparation method of the silica paste comprises: adding hydrophobic fumed silica to branched dimethyl silicone oil, heating and stirring for 25-35 minutes under the conditions of nitrogen gas flow at a temperature of 120-140° C., and after uniform mixing, adding a certain amount of dimethyl silicone oil to dilute the mixture to a silica mass fraction of 5%-10%, thereby obtaining the silica paste.

3. A defoamer with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance according to claim 2, characterized in that: The weight ratio of the branched dimethyl silicone oil to the hydrophobic fumed silica is (230-240):(4-6).

4. The defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance according to claim 1, characterized in that: The molecular structure of the end-capped polyether-modified polysiloxane is shown in Structural Formula 1: Structural formula 1.

5. The defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance according to claim 1, characterized in that: The compound polyether is composed of an allyl polyether with a number average molecular weight of 1220 and n(EO):n(PO)=3:1 in the molecule and an allyl polyether with a number average molecular weight of 800 and n(EO):n(PO)=1:4 in the molecule.

6. The defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance according to claim 5, characterized in that: The weight ratio of the allyl polyether in which n(EO):n(PO)=3:1 in the molecule to the allyl polyether in which n(EO):n(PO)=1:4 in the molecule is (1-2):(1-2).

7. The defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance according to claim 1, characterized in that: The thickener is obtained by neutralizing a functional modified polyether with glacial acetic acid, wherein the molecular structure of the functional modified polyether is shown in Structural Formula 2: Structural formula 2; The functional modified polyether preparation raw material includes a mixed long-chain alkyl glycidyl ether and a common polyether in a molar ratio of 1:1.1-1.2; and also includes 0.03-0.05% of aluminum isopropoxide added in an amount equal to the sum of the mass of the mixed long-chain alkyl glycidyl ether and the common polyether; The raw materials for preparing the mixed long-chain alkyl glycidyl ether include C 12-14 alcohol, epichlorohydrin, a phase transfer catalyst and an aqueous sodium hydroxide 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 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 common polyether include propylene alcohol, ethylene oxide and propylene oxide in a weight ratio of (250-280): (210-230): (56-60), and sodium hydroxide in a weight percentage of 0.08% of the total weight of propylene alcohol, propylene oxide and ethylene oxide.

8. The defoaming agent with fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance according to claim 7, characterized in that: The phase transfer catalyst is tetrabutylammonium bromide; the mass concentration of the sodium hydroxide aqueous solution is 14-16%.

9. The defoamer according to claim 1, which has fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance, is characterized in that: The sterilizing agent is potassium sorbate.

10. The defoamer according to claim 1, which has fast dispersion, low cloud point, high temperature and high pressure resistance, strong acid and strong alkali resistance, characterized in that: The preparation steps of the defoamer include: stirring white carbon black silicone paste, spherical polysilsesquioxane and blocked polyether modified polysiloxane with a homogenizer to fully mix them, then adding compound polyether, thickener, sterilizing agent and water to stir evenly, and then continuing to stir quickly with the homogenizer for 25-35 minutes to obtain a uniformly mixed polyether modified polysiloxane defoamer.

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