High-temperature-resistant modified defoamer and preparation method thereof

Abstract

The application relates to the technical field of fine chemical industry, and particularly relates to a high-temperature-resistant modified defoaming agent and a preparation method thereof. The high-temperature-resistant modified defoaming agent is prepared from epoxy-modified silicone oil, sulfonic acid group-terminated polyether, fumed silica, a crosslinking agent, a sulfonic acid type surfactant, an antioxidant and deionized water. The epoxy-modified silicone oil is used as a main defoaming skeleton. The fumed silica and the sulfonic acid type surfactant are used together to accelerate the dispersion of foam and improve the high-temperature resistance. Under the action of the crosslinking agent, the epoxy-modified silicone oil is condensed to build a three-dimensional network structure. Meanwhile, the epoxy group of the epoxy-modified silicone oil and the sulfonic acid group of the sulfonic acid group-terminated polyether are ring-opening reacted to build a molecular-level composite structure, so that synergistic effect is realized. Meanwhile, the problems of poor compatibility and weak stability of traditional organic silicon and polyether defoaming agents are overcome, the system stability is improved, and the defoaming and long-acting foam inhibiting effects can be maintained in an extreme environment with a temperature of 100 DEG C and pH>12.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fine chemical technology, and in particular to a high-temperature-resistant modified defoamer and a preparation method thereof. BACKGROUND

[0002] In industrial production of aqueous systems, high temperature and strong alkali environment often coexist, such as metal processing, high-temperature cleaning of equipment and utensils, etc. The appearance of foam in these scenes often becomes a stumbling block to production efficiency. Foam not only causes equipment operation to be blocked and energy consumption to be increased, but also can cause overflow problems.

[0003] Ordinary defoamers are prone to decomposition and failure in high-temperature (usually 80-100℃) or strong alkali (pH value higher than 12) environments, and cannot continuously inhibit foam. Existing composite defoamers are mostly realized by physical blending of organic silicon defoamers and polyether defoamers to achieve performance stacking, but the compatibility between components is poor, and stratification or precipitation easily occurs, affecting long-term stability. In extreme environments with temperature of 100℃ and pH>12, the adaptability is weak, the defoaming and foam inhibition effects are poor, and the continuous production requirements of industry cannot be met. SUMMARY

[0004] In order to overcome the shortcomings and deficiencies in the prior art, one of the purposes of the present application is to provide a high-temperature-resistant modified defoamer with high stability, which can still maintain good defoaming and long-acting foam inhibition effects in extreme environments with temperature of 100℃ and pH>12.

[0005] The second purpose of the present application is to provide a preparation method of the high-temperature-resistant modified defoamer, which is simple to operate, convenient to control, high in production efficiency, low in production cost, and can be used for large-scale production.

[0006] One of the purposes of the present application is realized by the following technical scheme: a high-temperature-resistant modified defoamer comprises the following raw materials by weight:

[0007] Epoxy-modified silicone oil 40-55 parts

[0008] Sulfonic acid-terminated polyether 20-30 parts

[0009] Fumed silica 3-6 parts

[0010] Crosslinking agent 2-4 parts

[0011] Sulfonic acid surfactant 1-3 parts

[0012] Antioxidant 0.5-1 part

[0013] Deionized water 10-35 parts.

[0014] This high-temperature modified defoamer exhibits high stability, maintaining good defoaming and long-lasting foam suppression effects even in extreme environments with temperatures up to 100℃ and pH > 12. It utilizes epoxy-modified silicone oil as the main defoaming framework, rapidly spreading on the foam film surface. The various groups work together to form a wedge-shaped structure, reducing local surface tension and causing the foam film to rupture. The high bond energy of the silicon-oxygen bonds and the chemical stability of the epoxy groups endow the defoamer with higher high-temperature resistance. Furthermore, the combined action of epoxy-modified silicone oil and fumed silica disrupts the mechanical balance of the foam film, improving spreadability. With the synergistic effect of sulfonic acid surfactants, it further reduces surface tension, causing the foam film to rapidly thin due to the pull of surrounding high-tension areas, accelerating foam dissipation. The added sulfonic acid end-capping... Polyethers, in a strongly alkaline environment, form a dynamic hydration layer that prevents foam regeneration. Furthermore, the strong acidity of their sulfonic acid groups forms ion pairs with basic ions, resisting hydrolysis and enhancing strong alkali stability. Under the action of a crosslinking agent, they condense to construct a three-dimensional network structure, encapsulating defoamer molecules and preventing them from being washed away by the liquid, thus prolonging the foam suppression time. Simultaneously, the ring-opening reaction between the epoxy groups of epoxy-modified silicone oil and the sulfonic acid groups of sulfonic acid-terminated polyethers constructs a molecular-level composite structure, achieving synergistic effects. This overcomes the problems of poor compatibility and weak stability in blending traditional organosilicon and polyether defoamers, improving the stability of the system.

[0015] Preferably, the preparation method of each part of the epoxy-modified silicone oil includes the following steps:

[0016] (R1) Take 70-90 parts by weight of octamethylcyclotetrasiloxane, 10-20 parts of hydroxyl-terminated polydimethylsiloxane, 0.1-1 parts of alkaline catalyst A, and 9-14 parts of epoxy monomer A, and set aside.

[0017] (R2) Under nitrogen protection, octamethylcyclotetrasiloxane, hydroxyl-terminated polydimethylsiloxane and alkaline catalyst A are added to the reactor and heated to 110-120℃ for ring-opening polymerization for 3-5 hours. Then, low-boiling substances are removed under vacuum to obtain hydroxyl-terminated organosilicon polymer.

[0018] (R3) After the reactor is cooled to 80-90℃, epoxy monomer A is added and copolymerized for 5-6 hours. Unreacted epoxy monomers are removed by rotary evaporation to obtain epoxy-modified silicone oil.

[0019] Using the above technical solution, octamethylcyclotetrasiloxane and hydroxyl-terminated polydimethylsiloxane undergo a ring-opening reaction under the action of alkaline catalyst A, and then copolymerize with epoxy monomer A to introduce epoxy groups. The high bond energy of the silicon-oxygen bond and the chemical stability of the epoxy groups endow the defoamer with high temperature resistance. Furthermore, the hydrophobic group (silyl group) is inserted into the gas-liquid interface, and the hydrophilic group (polyether segment) points towards the aqueous phase, forming a "wedge" structure, reducing local surface tension, and promoting the rupture of the foam film.

[0020] Preferably, the alkaline catalyst A is NaOH or KOH, and the epoxy monomer A is composed of propylene oxide and ethylene oxide in a weight ratio of 7-10:2-4.

[0021] Preferably, the preparation method of each portion of the sulfonic acid-terminated polyether includes the following steps:

[0022] (Q1) Take 60-80 parts by weight of polypropylene glycol, 11-16 parts of epoxy monomer B, 0.05-0.5 parts of alkaline catalyst B and 15-16 parts of sulfonating agent, and set aside.

[0023] (Q2) Polypropylene glycol, epoxy monomer B and alkaline catalyst B are added to a high-pressure reactor and polymerized at 140-150℃ for 6-8 hours under 0.2-0.5 MPa conditions to obtain block polyether;

[0024] (Q3) After the high-pressure reactor is cooled to 60-70℃, the sulfonating agent is added dropwise for 1 hour, and the reaction continues for 2-4 hours. After neutralization with alkali, the product is dried to obtain sulfonic acid-terminated polyether.

[0025] Using the above technical solution, polypropylene glycol is used as an initiator to randomly copolymerize with propylene oxide and ethylene oxide to generate block polyether; then it reacts with sulfonating agent chlorosulfonic acid to convert the terminal hydroxyl groups into sulfonic acid groups. The resulting sulfonic acid-terminated polyether can form a dynamic hydration layer in an alkaline environment, preventing foam regeneration. Furthermore, the strong acidity of the sulfonic acid groups forms ion pairs with the alkaline ions, which is beneficial for resisting hydrolysis, adapting to strong alkaline environments, and enhancing strong alkaline stability.

[0026] Preferably, the average molecular weight of the polypropylene glycol is 1000-3000, the alkaline catalyst B is NaOH or KOH, the epoxy monomer B is composed of propylene oxide and ethylene oxide in a weight ratio of 9-12:2-4, and the sulfonating agent is chlorosulfonic acid.

[0027] By adopting the above technical solution, the average molecular weight of polypropylene glycol is controlled between 1000 and 3000, so that the sulfonic acid-terminated polyether has both moderate hydrophilicity (terminal sulfonic acid group) and hydrophobicity (PPG main chain), forming an amphiphilic structure. This balances the chain segment length and flexibility, allowing the sulfonic acid-terminated polyether to quickly diffuse into the foam liquid film and also to insert into the liquid film through the hydrophobic chain segment, reducing the surface tension and achieving efficient defoaming.

[0028] Preferably, the fumed silica is selected from Evonik AEROSIL R972 and / or Hubei Huifu HB-139.

[0029] The above-mentioned technical solutions all use nano-hydrophobic fumed silica, which can be adsorbed on the surface of the foam film, hindering liquid drainage and film thinning, accelerating foam breaking, and working together with epoxy-modified silicone oil to effectively disrupt the mechanical balance of the foam film and improve its spreadability.

[0030] Preferably, the crosslinking agent is methyltrimethoxysilane and / or methyltributylone oxime silane.

[0031] Preferably, the sulfonic acid surfactant is sodium dodecylbenzenesulfonate or sodium dodecyl sulfate, which has good wetting, emulsifying and dispersing properties, and by reducing local surface tension, the foam liquid film is rapidly thinned by the pull of the surrounding high-tension area and eventually ruptures.

[0032] Preferably, the antioxidant is antioxidant 1076 or antioxidant 1010.

[0033] The second objective of this invention is achieved through the following technical solution: the preparation method of the above-mentioned high-temperature resistant modified defoamer includes the following steps:

[0034] (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside.

[0035] (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica to a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture.

[0036] (S3) Heat the mixture to 70-80℃, add a crosslinking agent, and react under alkaline conditions for 1.5-2.5h to form a three-dimensional network structure;

[0037] (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 1.5-2 hours, and cycle 3 times under pressure of 20 MPa using a homogenizer to obtain a high-temperature resistant modified defoamer.

[0038] Using the above technical solution, epoxy-modified silicone oil and sulfonic acid-terminated polyether form a three-dimensional network structure under crosslinking agent and alkaline conditions, which improves the stability of the system. Then, sulfonic acid surfactant, antioxidant and deionized water are added for emulsification and homogenization to obtain a stable emulsion.

[0039] The beneficial effects of the present invention are as follows: the high-temperature modified defoamer of the present invention has high stability and can still maintain good defoaming and long-lasting foam suppression effects in extreme environments with a temperature of 100°C and pH > 12.

[0040] The preparation method of the present invention is simple to operate, easy to control, has high production efficiency, low production cost, and can be used for large-scale production. Detailed Implementation

[0041] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0042] Example 1

[0043] A high-temperature resistant modified defoamer, comprising the following raw materials in parts by weight:

[0044] 50 parts epoxy modified silicone oil

[0045] 25 parts of sulfonic acid-terminated polyether

[0046] 4 parts of fumed silica

[0047] 3 parts crosslinking agent

[0048] 2 parts of sulfonic acid surfactant

[0049] Antioxidant 0.8 parts

[0050] 20 parts deionized water.

[0051] The preparation method of each part of the epoxy-modified silicone oil includes the following steps:

[0052] (R1) Take 80 parts by weight of octamethylcyclotetrasiloxane, 15 parts of hydroxyl-terminated polydimethylsiloxane, 0.5 parts of alkaline catalyst A, and 12 parts of epoxy monomer A, and set aside.

[0053] (R2) Under nitrogen protection, octamethylcyclotetrasiloxane, hydroxyl-terminated polydimethylsiloxane and alkaline catalyst A were added to the reactor and heated to 120°C for ring-opening polymerization for 4 hours. Then, low-boiling substances were removed under vacuum to obtain hydroxyl-terminated organosilicon polymer.

[0054] (R3) After the reactor is cooled to 85°C, epoxy monomer A is added and copolymerized for 5.5 hours. Unreacted epoxy monomers are removed by rotary evaporation to obtain epoxy-modified silicone oil.

[0055] The alkaline catalyst A is KOH, and the epoxy monomer A is composed of propylene oxide and ethylene oxide in a weight ratio of 9:3.

[0056] The preparation method of each of the sulfonic acid-terminated polyethers includes the following steps:

[0057] (Q1) Take 70 parts by weight of polypropylene glycol, 14 parts of epoxy monomer B, 0.3 parts of alkaline catalyst B and 15.5 parts of sulfonating agent, and set aside.

[0058] (Q2) Polypropylene glycol, epoxy monomer B and alkaline catalyst B are added to a high-pressure reactor and polymerized at 145°C for 7 hours under 0.3 MPa conditions to obtain block polyether;

[0059] (Q3) After the high-pressure reactor is cooled to 65°C, the sulfonating agent is added dropwise for 1 hour, and the reaction continues for 3 hours. After neutralization with alkali, the product is dried to obtain sulfonic acid-terminated polyether.

[0060] The average molecular weight of the polypropylene glycol is 2000, the alkaline catalyst B is KOH, the epoxy monomer B is composed of propylene oxide and ethylene oxide in a weight ratio of 10:3, and the sulfonating agent is chlorosulfonic acid.

[0061] The fumed silica is selected from Evonik AEROSIL R972.

[0062] The crosslinking agent is methyltrimethoxysilane.

[0063] The sulfonic acid surfactant is sodium dodecylbenzenesulfonate.

[0064] The antioxidant is antioxidant 1076.

[0065] The preparation method of the high-temperature resistant modified defoamer includes the following steps:

[0066] (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside.

[0067] (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica to a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture.

[0068] (S3) Heat the mixture to 80°C, add a crosslinking agent, and react under alkaline conditions for 2 hours to form a three-dimensional network structure;

[0069] (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 2 hours, and cycle 3 times under pressure of 20 MPa in a homogenizer to obtain a high-temperature resistant modified defoamer.

[0070] Example 2

[0071] A high-temperature resistant modified defoamer, comprising the following raw materials in parts by weight:

[0072] 40 parts of epoxy modified silicone oil

[0073] 20 parts of sulfonic acid-terminated polyether

[0074] 3 parts of fumed silica

[0075] 2 parts crosslinking agent

[0076] 1 part of sulfonic acid surfactant

[0077] 0.5 parts antioxidant

[0078] 10 parts deionized water.

[0079] The preparation method of each part of the epoxy-modified silicone oil includes the following steps:

[0080] (R1) Take 70 parts by weight of octamethylcyclotetrasiloxane, 10 parts of hydroxyl-terminated polydimethylsiloxane, 0.1 parts of alkaline catalyst A, and 9 parts of epoxy monomer A, and set aside.

[0081] (R2) Under nitrogen protection, octamethylcyclotetrasiloxane, hydroxyl-terminated polydimethylsiloxane and alkaline catalyst A were added to the reactor and heated to 120°C for ring-opening polymerization for 3 hours. Then, low-boiling substances were removed under vacuum to obtain hydroxyl-terminated organosilicon polymer.

[0082] (R3) After the reactor is cooled to 80°C, epoxy monomer A is added and copolymerized for 5 hours. Unreacted epoxy monomers are removed by rotary evaporation to obtain epoxy-modified silicone oil.

[0083] The alkaline catalyst A is KOH, and the epoxy monomer A is composed of propylene oxide and ethylene oxide in a weight ratio of 9:3.

[0084] The preparation method of each of the sulfonic acid-terminated polyethers includes the following steps:

[0085] (Q1) Take 60 parts by weight of polypropylene glycol, 11 parts of epoxy monomer B, 0.05 parts of alkaline catalyst B and 15 parts of sulfonating agent, and set aside.

[0086] (Q2) Polypropylene glycol, epoxy monomer B and alkaline catalyst B are added to a high-pressure reactor and polymerized at 150°C for 6 hours under 0.2 MPa conditions to obtain block polyether;

[0087] (Q3) After the high-pressure reactor is cooled to 60°C, the sulfonating agent is added dropwise for 1 hour, and the reaction continues for 2 hours. After neutralization with alkali, the product is dried to obtain sulfonic acid-terminated polyether.

[0088] The polypropylene glycol has an average molecular weight of 1000, the alkaline catalyst B is KOH, the epoxy monomer B is composed of propylene oxide and ethylene oxide in a weight ratio of 9:2, and the sulfonating agent is chlorosulfonic acid.

[0089] The fumed silica is selected from Evonik AEROSIL R972.

[0090] The crosslinking agent is methyltrimethoxysilane.

[0091] The sulfonic acid surfactant is sodium dodecylbenzenesulfonate.

[0092] The antioxidant is antioxidant 1076.

[0093] The preparation method of the high-temperature resistant modified defoamer includes the following steps:

[0094] (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside.

[0095] (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica to a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture.

[0096] (S3) Heat the mixture to 80°C, add a crosslinking agent, and react under alkaline conditions for 2 hours to form a three-dimensional network structure;

[0097] (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 2 hours, and cycle 3 times under pressure of 20 MPa in a homogenizer to obtain a high-temperature resistant modified defoamer.

[0098] Example 3

[0099] A high-temperature resistant modified defoamer, comprising the following raw materials in parts by weight:

[0100] 55 parts epoxy modified silicone oil

[0101] 30 parts of sulfonic acid-terminated polyether

[0102] 6 parts of fumed silica

[0103] 4 parts crosslinking agent

[0104] 3 parts of sulfonic acid surfactant

[0105] 1 part antioxidant

[0106] 35 parts of deionized water.

[0107] The preparation method of each part of the epoxy-modified silicone oil includes the following steps:

[0108] (R1) Take 90 parts by weight of octamethylcyclotetrasiloxane, 20 parts of hydroxyl-terminated polydimethylsiloxane, 1 part of alkaline catalyst A, and 14 parts of epoxy monomer A, and set aside.

[0109] (R2) Under nitrogen protection, octamethylcyclotetrasiloxane, hydroxyl-terminated polydimethylsiloxane and alkaline catalyst A were added to the reactor and heated to 120°C for ring-opening polymerization for 5 hours. Then, low-boiling substances were removed under vacuum to obtain hydroxyl-terminated organosilicon polymer.

[0110] (R3) After the reactor is cooled to 90°C, epoxy monomer A is added and copolymerized for 6 hours. Unreacted epoxy monomers are removed by rotary evaporation to obtain epoxy-modified silicone oil.

[0111] The alkaline catalyst A is KOH, and the epoxy monomer A is composed of propylene oxide and ethylene oxide in a weight ratio of 9:3.

[0112] The preparation method of each of the sulfonic acid-terminated polyethers includes the following steps:

[0113] (Q1) Take 80 parts by weight of polypropylene glycol, 16 parts of epoxy monomer B, 0.5 parts of alkaline catalyst B and 16 parts of sulfonating agent, and set aside.

[0114] (Q2) Polypropylene glycol, epoxy monomer B and alkaline catalyst B are added to a high-pressure reactor and polymerized at 140°C for 8 hours under 0.5 MPa conditions to obtain block polyether.

[0115] (Q3) After the high-pressure reactor is cooled to 70°C, the sulfonating agent is added dropwise for 1 hour, and the reaction continues for 4 hours. After neutralization with alkali, the product is dried to obtain sulfonic acid-terminated polyether.

[0116] The polypropylene glycol has an average molecular weight of 3000, the alkaline catalyst B is KOH, the epoxy monomer B is composed of propylene oxide and ethylene oxide in a weight ratio of 12:4, and the sulfonating agent is chlorosulfonic acid.

[0117] The fumed silica is selected from Evonik AEROSIL R972.

[0118] The crosslinking agent is methyltrimethoxysilane.

[0119] The sulfonic acid surfactant is sodium dodecylbenzenesulfonate.

[0120] The antioxidant is antioxidant 1076.

[0121] The preparation method of the high-temperature resistant modified defoamer includes the following steps:

[0122] (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside.

[0123] (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica to a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture.

[0124] (S3) Heat the mixture to 80°C, add a crosslinking agent, and react under alkaline conditions for 2 hours to form a three-dimensional network structure;

[0125] (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 2 hours, and cycle 3 times under pressure of 20 MPa in a homogenizer to obtain a high-temperature resistant modified defoamer.

[0126] Example 4

[0127] A high-temperature resistant modified defoamer, comprising the following raw materials in parts by weight:

[0128] 45 parts of epoxy-modified silicone oil

[0129] 28 parts of sulfonic acid-terminated polyether

[0130] 5 parts of fumed silica

[0131] 4 parts crosslinking agent

[0132] 2 parts of sulfonic acid surfactant

[0133] Antioxidant 0.6 parts

[0134] 30 parts deionized water.

[0135] The preparation method of each part of the epoxy-modified silicone oil includes the following steps:

[0136] (R1) Take 75 parts by weight of octamethylcyclotetrasiloxane, 17 parts by weight of hydroxyl-terminated polydimethylsiloxane, 0.8 parts by weight of alkaline catalyst A, and 12 parts by weight of epoxy monomer A, and set aside.

[0137] (R2) Under nitrogen protection, octamethylcyclotetrasiloxane, hydroxyl-terminated polydimethylsiloxane and alkaline catalyst A were added to the reactor and heated to 120°C for ring-opening polymerization for 5 hours. Then, low-boiling substances were removed under vacuum to obtain hydroxyl-terminated organosilicon polymer.

[0138] (R3) After the reactor is cooled to 88°C, epoxy monomer A is added and copolymerized for 5.8 hours. Unreacted epoxy monomers are removed by rotary evaporation to obtain epoxy-modified silicone oil.

[0139] The alkaline catalyst A is KOH, and the epoxy monomer A is composed of propylene oxide and ethylene oxide in a weight ratio of 9:3.

[0140] The preparation method of each of the sulfonic acid-terminated polyethers includes the following steps:

[0141] (Q1) Take 65 parts by weight of polypropylene glycol, 15 parts of epoxy monomer B, 0.2 parts of alkaline catalyst B and 16 parts of sulfonating agent, and set aside.

[0142] (Q2) Polypropylene glycol, epoxy monomer B and alkaline catalyst B are added to a high-pressure reactor and polymerized at 150°C for 8 hours under 0.4 MPa conditions to obtain block polyether.

[0143] (Q3) After the high-pressure reactor is cooled to 68°C, the sulfonating agent is added dropwise for 1 hour, and the reaction continues for 2 hours. After neutralization with alkali, the product is dried to obtain sulfonic acid-terminated polyether.

[0144] The polypropylene glycol has an average molecular weight of 2000, the alkaline catalyst B is KOH, the epoxy monomer B is composed of propylene oxide and ethylene oxide in a weight ratio of 10:2, and the sulfonating agent is chlorosulfonic acid.

[0145] The fumed silica is selected from Evonik AEROSIL R972.

[0146] The crosslinking agent is methyltrimethoxysilane.

[0147] The sulfonic acid surfactant is sodium dodecylbenzenesulfonate.

[0148] The antioxidant is antioxidant 1076.

[0149] The preparation method of the high-temperature resistant modified defoamer includes the following steps:

[0150] (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside.

[0151] (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica to a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture.

[0152] (S3) The mixture is heated to 80°C, a crosslinking agent is added, and the mixture is reacted under alkaline conditions for 2 hours to form a three-dimensional network structure.

[0153] (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 2 hours, and cycle 3 times under pressure of 20 MPa in a homogenizer to obtain a high-temperature resistant modified defoamer.

[0154] Comparative Example 1

[0155] The difference between this comparative example and Example 1 is as follows:

[0156] The epoxy-modified silicone oil was replaced with polydimethylsiloxane, CAS No. 9016-00-6.

[0157] Comparative Example 2

[0158] The difference between this comparative example and Example 1 is as follows:

[0159] The preparation method of the high-temperature resistant modified defoamer includes the following steps:

[0160] (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside.

[0161] (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica to a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture.

[0162] (S3) Heat the mixture to 80°C, add a crosslinking agent and react for 2 hours to form a three-dimensional network structure;

[0163] (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 2 hours, and cycle 3 times under pressure of 20 MPa in a homogenizer to obtain a high-temperature resistant modified defoamer.

[0164] Comparative Example 3

[0165] The difference between this comparative example and Example 1 is as follows:

[0166] A high-temperature resistant modified defoamer, comprising the following raw materials in parts by weight:

[0167] 53 parts of epoxy-modified silicone oil

[0168] 25 parts of sulfonic acid-terminated polyether

[0169] 4 parts of fumed silica

[0170] 2 parts of sulfonic acid surfactant

[0171] Antioxidant 0.8 parts

[0172] 20 parts deionized water.

[0173] The preparation method of each part of the epoxy-modified silicone oil includes the following steps:

[0174] (R1) Take 80 parts by weight of octamethylcyclotetrasiloxane, 15 parts of hydroxyl-terminated polydimethylsiloxane, 0.5 parts of alkaline catalyst A, and 12 parts of epoxy monomer A, and set aside.

[0175] (R2) Under nitrogen protection, octamethylcyclotetrasiloxane, hydroxyl-terminated polydimethylsiloxane and alkaline catalyst A were added to the reactor and heated to 120°C for ring-opening polymerization for 4 hours. Then, low-boiling substances were removed under vacuum to obtain hydroxyl-terminated organosilicon polymer.

[0176] (R3) After the reactor is cooled to 85°C, epoxy monomer A is added and copolymerized for 5.5 hours. Unreacted epoxy monomers are removed by rotary evaporation to obtain epoxy-modified silicone oil.

[0177] The alkaline catalyst A is KOH, and the epoxy monomer A is composed of propylene oxide and ethylene oxide in a weight ratio of 9:3.

[0178] The preparation method of each of the sulfonic acid-terminated polyethers includes the following steps:

[0179] (Q1) Take 70 parts by weight of polypropylene glycol, 14 parts of epoxy monomer B, 0.3 parts of alkaline catalyst B and 15.5 parts of sulfonating agent, and set aside.

[0180] (Q2) Polypropylene glycol, epoxy monomer B and alkaline catalyst B are added to a high-pressure reactor and polymerized at 145°C for 7 hours under 0.3 MPa conditions to obtain block polyether;

[0181] (Q3) After the high-pressure reactor is cooled to 65°C, the sulfonating agent is added dropwise for 1 hour, and the reaction continues for 3 hours. After neutralization with alkali, the product is dried to obtain sulfonic acid-terminated polyether.

[0182] The average molecular weight of the polypropylene glycol is 2000, the alkaline catalyst B is KOH, the epoxy monomer B is composed of propylene oxide and ethylene oxide in a weight ratio of 10:3, and the sulfonating agent is chlorosulfonic acid.

[0183] The fumed silica is selected from Evonik AEROSIL R972.

[0184] The sulfonic acid surfactant is sodium dodecylbenzenesulfonate.

[0185] The antioxidant is antioxidant 1076.

[0186] The preparation method of the high-temperature resistant modified defoamer includes the following steps:

[0187] (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside.

[0188] (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica to a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture.

[0189] (S3) The mixture is heated to 80°C and reacted under alkaline conditions for 2 hours to form a polymer;

[0190] (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the polymer, emulsify by high-speed shearing at 2500 rpm for 2 hours, and cycle 3 times under pressure of 20 MPa in a homogenizer to obtain high-temperature resistant modified defoamer.

[0191] Performance testing

[0192] The high-temperature modified defoamers of Examples 1-4 and Comparative Examples 1-3 were used to test their stability and defoaming performance in an extreme environment with a temperature of 100°C and a pH of 12. The test conditions are as follows:

[0193] Samples: Take the high-temperature resistant modified defoamers of Examples 1-4 and Comparative Examples 1-3, dilute them with deionized water (the volume ratio of deionized water to high-temperature resistant modified defoamer is 1:2), sterilize them at 121℃, and then cool them to obtain samples;

[0194] The strong alkaline foaming solution is composed of the following components in weight percentage: 0.5% nonylphenol polyoxyethylene (10) ether, 0.5% sodium dodecylbenzene sulfonate, 1% sodium hydroxide and the balance deionized water.

[0195] (1) Stability test

[0196] Take 8 mL of sample from two 10 mL graduated centrifuge tubes and place them symmetrically into an 80-2 type low-speed electric centrifuge. Rotate the tubes continuously at 3000 r / min for 15 min. Remove the tubes and read the volume of the layered liquid. The arithmetic mean of the two measurements is taken as the result.

[0197] (2) Defoaming performance

[0198] Take a 1000mL graduated beaker, add 100mL of strong alkali foaming solution and 0.1mL of high-temperature resistant modified defoamer, and place it in a constant temperature oil bath at 100℃. Heat the strong alkali foaming solution to 100℃ and keep it boiling continuously. Record the highest foam mark after 3 minutes.

[0199] The test results are shown in Table 1:

[0200] Table 1

[0201]

[0202] As shown in Table 1 above, the high-temperature modified defoamer of the present invention has high stability and can maintain good defoaming and long-lasting foam suppression effects even in extreme environments with a temperature of 100℃ and pH > 12.

[0203] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A high-temperature resistant modified defoamer, characterized in that, The ingredients include the following parts by weight: 40-55 parts of epoxy modified silicone oil 20-30 parts of sulfonic acid-terminated polyether 3-6 parts of fumed silica 2-4 parts crosslinking agent 1-3 parts of sulfonic acid surfactant Antioxidant 0.5-1 part 10-35 parts deionized water; The preparation method of the high-temperature resistant modified defoamer includes the following steps: (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside. (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica into a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture. (S3) Heat the mixture to 70-80℃, add a crosslinking agent, and react under alkaline conditions for 1.5-2.5h to form a three-dimensional network structure; (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 1.5-2 hours, and cycle 3 times under pressure of 20 MPa using a homogenizer to obtain a high-temperature resistant modified defoamer.

2. The high-temperature resistant modified defoamer according to claim 1, characterized in that: The preparation method of each part of the epoxy-modified silicone oil includes the following steps: (R1) Take 70-90 parts by weight of octamethylcyclotetrasiloxane, 10-20 parts of hydroxyl-terminated polydimethylsiloxane, 0.1-1 parts of alkaline catalyst A, and 9-14 parts of epoxy monomer A, and set aside. (R2) Under nitrogen protection, octamethylcyclotetrasiloxane, hydroxyl-terminated polydimethylsiloxane and alkaline catalyst A are added to the reactor and heated to 110-120℃ for ring-opening polymerization for 3-5 hours. Then, low-boiling substances are removed under vacuum to obtain hydroxyl-terminated organosilicon polymer. (R3) After the reactor is cooled to 80-90℃, epoxy monomer A is added and copolymerized for 5-6 hours. Unreacted epoxy monomers are removed by rotary evaporation to obtain epoxy-modified silicone oil.

3. The high-temperature resistant modified defoamer according to claim 2, characterized in that: The alkaline catalyst A is NaOH or KOH, and the epoxy monomer A is composed of propylene oxide and ethylene oxide in a weight ratio of 7-10:2-4.

4. The high-temperature resistant modified defoamer according to claim 1, characterized in that: The preparation method of each of the sulfonic acid-terminated polyethers includes the following steps: (Q1) Take 60-80 parts by weight of polypropylene glycol, 11-16 parts of epoxy monomer B, 0.05-0.5 parts of alkaline catalyst B and 15-16 parts of sulfonating agent, and set aside. (Q2) Polypropylene glycol, epoxy monomer B and alkaline catalyst B are added to a high-pressure reactor and polymerized at 140-150℃ for 6-8 hours under 0.2-0.5 MPa conditions to obtain block polyether; (Q3) After the high-pressure reactor is cooled to 60-70℃, the sulfonating agent is added dropwise for 1 hour, and the reaction continues for 2-4 hours. After neutralization with alkali, the product is dried to obtain sulfonic acid-terminated polyether.

5. The high-temperature resistant modified defoamer according to claim 4, characterized in that: The average molecular weight of the polypropylene glycol is 1000-3000, the alkaline catalyst B is NaOH or KOH, the epoxy monomer B is composed of propylene oxide and ethylene oxide in a weight ratio of 9-12:2-4, and the sulfonating agent is chlorosulfonic acid.

6. The high-temperature resistant modified defoamer according to claim 1, characterized in that: The fumed silica is selected from Evonik AEROSIL R972 and / or Hubei Huifu HB-139.

7. The high-temperature resistant modified defoamer according to claim 1, characterized in that: The crosslinking agent is methyltrimethoxysilane and / or methyltributylone oxime silane.

8. The high-temperature resistant modified defoamer according to claim 1, characterized in that: The sulfonic acid surfactant is sodium dodecylbenzenesulfonate or sodium dodecyl sulfate.

9. The high-temperature resistant modified defoamer according to claim 1, characterized in that: The antioxidant is antioxidant 1076 or antioxidant 1010.

10. A method for preparing a high-temperature resistant modified defoamer as described in any one of claims 1-9, characterized in that, Includes the following steps: (S1) Take epoxy modified silicone oil, sulfonic acid-terminated polyether, fumed silica, crosslinking agent, sulfonic acid surfactant, antioxidant and deionized water in parts by weight, and set aside. (S2) Add epoxy modified silicone oil, sulfonic acid-terminated polyether and fumed silica into a high-speed disperser and stir evenly at 1500 rpm to obtain a mixture. (S3) Heat the mixture to 70-80℃, add a crosslinking agent, and react under alkaline conditions for 1.5-2.5h to form a three-dimensional network structure; (S4) Add sulfonic acid surfactant, antioxidant and deionized water to the three-dimensional network structure, emulsify by high-speed shearing at 2500 rpm for 1.5-2 hours, and cycle 3 times under pressure of 20 MPa using a homogenizer to obtain a high-temperature resistant modified defoamer.

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