Emulsion type defoaming agent with excellent stability and preparation method thereof

Abstract

The invention relates to the technical field of defoaming agents, and discloses an emulsion type defoaming agent with excellent stability and a preparation method thereof.The preparation method comprises the steps that white carbon black and graphene are modified and react to obtain modified filler, the modified filler and hydrogen-containing silicone oil are subjected to an addition reaction to obtain modified organic silicon, and the modified organic silicon is subjected to a reaction to obtain the emulsion type defoaming agent. The modified organic silicon, the thickening agent, the emulsifying agent and the deionized water are stirred and mixed to obtain the emulsion type defoaming agent with excellent stability, the white carbon black and the graphene of the defoaming agent have a synergistic effect and are matched with each other, after modification, the defoaming agent can be uniformly dispersed in a matrix to form a more stable defoaming system, the stability of the product is enhanced, the preparation process is simple, and the preparation method is suitable for industrial production. The foaming agent has the advantages of easily available raw materials, low cost, capability of rapidly eliminating and preventing foam generation, effective improvement of the production efficiency, good stability, difficult layering phenomenon, and good dispersibility and storage stability.

Description

Technical Field

[0001] The invention relates to the technical field of defoamers, in particular to an emulsion defoamer with excellent stability and a preparation method thereof. Background Art

[0002] In many industrial production processes, such as food, medicine, coatings and other industries, a large amount of foam is often generated due to stirring, vibration, boiling and the addition of surfactants. The presence of foam will cause a decrease in product quality and production capacity. In order to avoid this phenomenon, defoamers are needed to inhibit and eliminate foam. There are many types of defoamers. From the composition, defoamers can be roughly divided into three types: silicone type, polyether type and non-silicone type. Among them, silicone is an excellent defoamer with strong foam removal ability and a wide range of applications. However, traditional silicone defoamers have poor dispersibility in aqueous phase systems, and are prone to uneven dispersion, incomplete emulsification, demulsification and oil floating. The stability is affected, which greatly limits the application of silicone defoamers.

[0003] Emulsion-type silicone defoamers not only have strong defoaming power, but also good anti-foaming effect. They are applicable to both non-aqueous phases and aqueous phases. However, emulsion is a thermodynamically unstable system. If the emulsification is not complete, as the storage time increases, the emulsion is prone to stratification, demulsification and other phenomena, making it difficult to exert the excellent properties of the emulsion, and then reducing its defoaming performance. Chinese patent CN106868935A discloses a defoamer for papermaking and a preparation method thereof. The defoamer includes modified dimethyl siloxane, modified polyoxyethylene ether, silicon dioxide, emulsifier, nonionic surfactant, and thickener. It is resistant to high temperature and strong alkali, and can quickly defoam under high temperature and strong alkali conditions, and has a long-lasting anti-foaming and defoaming effect, but the stability and uniformity of the defoamer are poor. Chinese patent application CN105289048A discloses a silicone-modified polyether ester emulsion defoamer and a preparation method thereof. Polyoxypropylene polyoxyethylene pentaerythritol ether fatty acid ester reacts with hydrogen-containing silicone oil under the action of a catalyst to obtain a silicone-modified polyether ester, which is emulsified with a composite emulsifier to obtain a silicone-modified polyether ester emulsion defoamer. The silicone-modified polyether ester emulsion defoamer has excellent defoaming and anti-foaming properties, but the dispersion effect and stability of the emulsion defoamer are average.

[0004] Therefore, it is of great significance to develop an emulsion defoamer with good stability, defoaming and anti-foaming effects. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In order to solve the above technical problems, the present invention provides an emulsion defoamer with excellent stability and a preparation method thereof. The emulsion defoamer has excellent stability as well as excellent defoaming and antifoaming capabilities.

[0007] (II) Technical solution

[0008] In order to achieve the above object, the present invention discloses a method for preparing an emulsion defoamer with excellent stability, comprising the following steps:

[0009] Step 1, ultrasonically disperse the white carbon black in an ethanol solution, adjust the pH to 3-4 with an acetic acid solution, add γ-glycidyloxypropyltrimethoxysilane, heat, mix evenly, react, cool after the reaction, centrifuge, wash with anhydrous ethanol, and dry in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black;

[0010] Step 2, ultrasonically dispersing the epoxidized silica in toluene, mixing evenly, adding 9-octadecene-1,12-diol, heating, mixing, reacting, and after the reaction is completed, filtering, washing with methanol, and drying in a drying oven at 60° C. for 24 hours to obtain modified silica;

[0011] Step 3: Ultrasonic dispersion of carboxylated graphene in N,N-dimethylformamide, uniform dispersion, adding modified white carbon black, heating, adding a catalyst, stirring and mixing, reacting, and after the reaction is completed, filtering, washing with anhydrous ethanol, and drying in a vacuum drying oven at 60° C. for 12 h to obtain a fatty alcohol modified filler;

[0012] Step 4: mixing hydrogen-containing silicone oil, fatty alcohol-modified filler and chloroplatinic acid, heating in a nitrogen atmosphere, reacting, and obtaining modified organosilicon after the reaction is completed;

[0013] Step 5: Evenly mix the modified silicone and thickener, heat to 40-50°C, stir for 1-2h, add the emulsifier, stir for 15-30min, then add deionized water, stir for 30-45min, and cool to obtain an emulsion defoamer with excellent stability.

[0014] Preferably, in the step 1, the mass ratio of white carbon black, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:950-1200:12-15.

[0015] Preferably, the reaction temperature in step 1 is 55-65° C., and the reaction time is 4-6 h.

[0016] Preferably, the ethanol solution in step 1 is a 95% ethanol aqueous solution.

[0017] Preferably, in step 2, the mass ratio of epoxidized white carbon black, toluene and 9-octadecene-1,12-diol is 100:1200-1500:85-102.

[0018] Preferably, the reaction temperature in step 2 is 105-115° C., and the reaction time is 12-15 h.

[0019] Preferably, in step three, the mass ratio of carboxylated graphene, N,N-dimethylformamide, modified silica, and catalyst is 15-25:3500-4800:100:0.5-0.8.

[0020] Preferably, the preparation method of carboxylated graphene in step three is as follows: 40 mL of graphene oxide dispersion and 60 mL of deionized water are mixed evenly, and then 5.0 g of sodium hydroxide and 7.5 g of sodium chloroacetate are added, mixed for 8 hours, centrifuged at a rate of 8000 r / min, centrifuged for 5 minutes, washed, neutralized, dialyzed, and dried at 60° C. for 12 hours to obtain carboxylated graphene.

[0021] Furthermore, the graphene oxide dispersion was purchased from Beijing Carbon Century Technology Co., Ltd., model number CCTGO-204.

[0022] Preferably, the catalyst in step three is p-toluenesulfonic acid.

[0023] Preferably, the reaction temperature in step 3 is 100-110° C., and the reaction time is 5-8 h.

[0024] Preferably, in step 4, the mass ratio of hydrogen-containing silicone oil, fatty alcohol-modified filler and chloroplatinic acid is 100:6-10:0.2-0.4.

[0025] Preferably, the reaction temperature in step 4 is 95-130° C., and the reaction time is 4-6 h.

[0026] Preferably, in step 5, the mass ratio of modified silicone, thickener, emulsifier and deionized water is 100:0.3-0.5:6-9:105-140.

[0027] Preferably, the thickener in step 5 includes one or more of carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose.

[0028] Preferably, in step 5, the emulsifier consists of Span 80 and Tween 80 in a mass ratio of 3:2.

[0029] An emulsion type defoamer with excellent stability is prepared by using the method for preparing an emulsion type defoamer with excellent stability.

[0030] (III) Beneficial technical effects

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) In the present invention, γ-glycidyloxypropyltrimethoxysilane is used to modify silica, and epoxy groups are introduced on the surface of silica to obtain epoxidized silica. The epoxidized silica reacts with some hydroxyl groups on 9-octadecene-1,12-diol, and the epoxy groups are ring-opened, introducing a large number of hydroxyl groups to obtain modified silica. The hydroxyl groups on the modified silica and the carboxyl groups on the carboxylated graphene react under the action of a catalyst to obtain a fatty alcohol modified filler. The alkenyl groups on the fatty alcohol modified filler and the hydrogenated silicone oil react under the action of the catalyst chloroplatinic acid to obtain a modified organosilicon. The modified organosilicon, thickener, and emulsifier work together and are mixed with deionized water to obtain an emulsion-type defoamer with excellent stability. The composite emulsifier enhances the balance and stability of the system and improves the comprehensive performance of the emulsion. Carboxymethyl cellulose has excellent thickening, film-forming and stability properties, which can improve the consistency of the silicone defoamer system, help form a stable film layer, and help adhere and disperse the active ingredients of the defoamer, thereby improving the defoaming effect and the stability of the system. Hydrogen-containing silicone oil can be used for defoaming in both water systems and oil systems, and has a wide range of applications. The surface tension of hydrogen-containing silicone oil is low, which enables it to more effectively reduce the surface tension of the foaming system, effectively break the already generated foam, prevent the generation of foam, and play a defoaming role. At the same time, it can also inhibit the generation of foam and reduce the foam in the system. Hydrogen-containing silicone oil has high heat resistance and can maintain stable performance over a wide temperature range.

[0033] (2) The emulsion defoamer of the present invention has the ability to quickly eliminate and prevent the generation of foam, can effectively improve production efficiency, and has good stability, is not prone to stratification, and has good dispersibility and storage stability. Due to its small particle size, large specific surface area, high surface energy, and three-dimensional network structure, white carbon black constitutes a large number of basic defoaming units, which can effectively adsorb bubbles and cause the bubbles to burst under the action of the low surface force of silicone oil. Furthermore, after the white carbon black is modified, it can be evenly and stably distributed in the system, which greatly improves the defoaming efficiency. At the same time, white carbon black also plays a role in thickening and preventing sedimentation, thereby improving the storage stability of the system. Graphene has a large specific surface area and loading sites, and can undergo physical adsorption with other substances, thereby enhancing the stability of the defoamer. Furthermore, graphene has the advantages of high temperature resistance and acid and alkali resistance, which can greatly improve the comprehensive performance of the system and improve its stability. White carbon black and graphene work synergistically and cooperate with each other. After modification, they can be evenly dispersed in the matrix to form a more stable defoaming system, enhance the stability of the product, and further improve the defoaming and anti-foaming performance of the defoamer.

[0034] (3) After the reaction of white carbon black and graphene in the present invention, the dispersibility of white carbon black and graphene can be effectively improved, and the reaction with hydrogen-containing silicone oil can make the dispersibility and compatibility of each raw material in the defoamer system excellent. The use of long-chain fatty alcohols to modify silicone can quickly reduce the surface tension of the liquid, destroy the stability of the foam, thereby effectively eliminating the foam, and can also inhibit the regeneration of the foam for a long time. At the same time, it has better spreadability and adsorption, quickly spreads on the foam surface, and adsorbs on the gas-liquid interface of the bubble, causing the bubble to burst quickly. Through chemical reactions, the stability and defoaming effect of the defoamer are further enhanced. The preparation process of the emulsion defoamer is simple, the raw materials are easy to obtain, and the cost is low. The prepared emulsion defoamer has the characteristics of high efficiency and stability while maintaining good defoaming and anti-foaming performance, and has a wide range of uses. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] A method for preparing an emulsion defoamer with excellent stability comprises the following steps:

[0038] Step 1, ultrasonically disperse the white carbon black in a 95% ethanol aqueous solution, adjust the pH to 3 with an acetic acid solution, and then add γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of white carbon black, ethanol solution, and γ-glycidyloxypropyltrimethoxysilane is 100:950:12, heat up, mix evenly, react at 55°C for 6 hours, and after the reaction is completed, cool, centrifuge, wash with anhydrous ethanol, and dry in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black;

[0039] Step 2, ultrasonically disperse the epoxidized silica in toluene, mix evenly, add 9-octadecene-1,12-diol, wherein the mass ratio of the epoxidized silica, toluene, and 9-octadecene-1,12-diol is 100:1200:85, heat, mix, react at 105°C, and react for 15 hours. After the reaction is completed, filter, wash with methanol, and dry in a drying oven at 60°C for 24 hours to obtain modified silica;

[0040] Step 3, using carboxylated graphene to be ultrasonically dispersed in N,N-dimethylformamide, after being evenly dispersed, adding modified white carbon black, heating, adding catalyst p-toluenesulfonic acid, wherein the mass ratio of carboxylated graphene, N,N-dimethylformamide, modified white carbon black, and catalyst p-toluenesulfonic acid is 15:3500:100:0.5, stirring and mixing, reacting at 100°C for 8 hours, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying in a vacuum drying oven at 60°C for 12 hours to obtain a fatty alcohol modified filler;

[0041] Step 4: Mix hydrogenated silicone oil, fatty alcohol modified filler and chloroplatinic acid in a mass ratio of 100:6:0.2, heat in a nitrogen atmosphere, react at 95° C. for 6 hours, and obtain modified organosilicon after the reaction is completed;

[0042] Step 5: Evenly mix the modified silicone and thickener carboxymethyl cellulose, heat to 40°C, stir for 2 hours, add an emulsifier consisting of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 15 minutes, then add deionized water, wherein the mass ratio of the modified silicone, thickener, emulsifier and deionized water is 100:0.3:6:105, stir for 30 minutes, cool, and obtain an emulsion defoamer with excellent stability.

[0043] Example 2

[0044] A method for preparing an emulsion defoamer with excellent stability comprises the following steps:

[0045] Step 1, ultrasonically disperse the white carbon black in a 95% ethanol aqueous solution, adjust the pH to 3.5 with an acetic acid solution, and then add γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of the white carbon black, the ethanol solution, and the γ-glycidyloxypropyltrimethoxysilane is 100:1100:14, heat up, mix evenly, react at 60°C for 5 hours, and after the reaction is completed, cool, centrifuge, wash with anhydrous ethanol, and dry in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black;

[0046] Step 2, ultrasonically disperse the epoxidized silica in toluene, mix evenly, add 9-octadecene-1,12-diol, wherein the mass ratio of the epoxidized silica, toluene, and 9-octadecene-1,12-diol is 100:1400:95, heat up, mix, react at 110°C, and react for 14 hours. After the reaction is completed, filter, wash with methanol, and dry in a drying oven at 60°C for 24 hours to obtain modified silica;

[0047] Step 3, using carboxylated graphene to be ultrasonically dispersed in N,N-dimethylformamide, after being evenly dispersed, adding modified white carbon black, heating, adding catalyst p-toluenesulfonic acid, wherein the mass ratio of carboxylated graphene, N,N-dimethylformamide, modified white carbon black, and catalyst p-toluenesulfonic acid is 21:4200:100:0.7, stirring and mixing, reacting at 105°C for 6 hours, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying in a vacuum drying oven at 60°C for 12 hours to obtain a fatty alcohol modified filler;

[0048] Step 4: Mix hydrogenated silicone oil, fatty alcohol modified filler and chloroplatinic acid in a mass ratio of 100:8:0.25, heat in a nitrogen atmosphere, react at 105° C. for 5 hours, and obtain modified organosilicon after the reaction is completed;

[0049] Step 5: Evenly mix the modified silicone and thickener carboxymethyl cellulose, heat to 45°C, stir for 1.5 hours, add an emulsifier consisting of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 18 minutes, and then add deionized water, wherein the mass ratio of the modified silicone, thickener, emulsifier, and deionized water is 100:0.35:7:118, stir for 35 minutes, and cool to obtain an emulsion defoamer with excellent stability.

[0050] Example 3

[0051] A method for preparing an emulsion defoamer with excellent stability comprises the following steps:

[0052] Step 1: Mix hydrogen-containing silicone oil, fatty alcohol-modified filler and chloroplatinic acid in a mass ratio of 100:9:0.35, heat in a nitrogen atmosphere, react at 120° C. for 5 hours, and obtain modified silicone after the reaction is completed;

[0053] Step 2: Evenly mix the modified silicone and thickener carboxymethyl cellulose, heat to 45°C, stir for 1.5 hours, add an emulsifier consisting of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 25 minutes, then add deionized water, wherein the mass ratio of the modified silicone, thickener, emulsifier and deionized water is 100:0.45:8:130, stir for 40 minutes, cool, and obtain an emulsion defoamer with excellent stability.

[0054] The preparation method of the fatty alcohol modified filler is the same as the preparation method of the fatty alcohol modified filler in Example 2.

[0055] Example 4

[0056] A method for preparing an emulsion defoamer with excellent stability comprises the following steps:

[0057] Step 1, ultrasonically disperse the white carbon black in a 95% ethanol aqueous solution, adjust the pH to 4 with an acetic acid solution, and then add γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of white carbon black, ethanol solution, and γ-glycidyloxypropyltrimethoxysilane is 100:1200:15, heat up, mix evenly, react at 65°C for 4 hours, and after the reaction is completed, cool, centrifuge, wash with anhydrous ethanol, and dry in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black;

[0058] Step 2, ultrasonically disperse the epoxidized silica in toluene, mix evenly, add 9-octadecene-1,12-diol, wherein the mass ratio of the epoxidized silica, toluene, and 9-octadecene-1,12-diol is 100:1500:102, heat, mix, react at 115°C, react for 12 hours, filter after the reaction, wash with methanol, and dry in a drying oven at 60°C for 24 hours to obtain modified silica;

[0059] Step 3, using carboxylated graphene to be ultrasonically dispersed in N,N-dimethylformamide, after being evenly dispersed, adding modified white carbon black, heating, adding catalyst p-toluenesulfonic acid, wherein the mass ratio of carboxylated graphene, N,N-dimethylformamide, modified white carbon black, and catalyst p-toluenesulfonic acid is 25:4800:100:0.8, stirring and mixing, reacting at 110°C for 5 hours, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying in a vacuum drying oven at 60°C for 12 hours to obtain a fatty alcohol modified filler;

[0060] Step 4: Mix hydrogenated silicone oil, fatty alcohol modified filler and chloroplatinic acid in a mass ratio of 100:10:0.4, heat in a nitrogen atmosphere, react at 130° C. for 4 hours, and obtain modified organosilicon after the reaction is completed;

[0061] Step 5: Evenly mix the modified silicone and thickener carboxymethyl cellulose, heat to 50°C, stir for 1 hour, add an emulsifier consisting of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 30 minutes, then add deionized water, wherein the mass ratio of the modified silicone, thickener, emulsifier and deionized water is 100:0.5:9:140, stir for 45 minutes, cool, and obtain an emulsion defoamer with excellent stability.

[0062] Comparative Example 1

[0063] A method for preparing an emulsion defoamer comprises the following steps:

[0064] Step 1, ultrasonically disperse the white carbon black in a 95% ethanol aqueous solution, adjust the pH to 3.5 with an acetic acid solution, and then add γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of the white carbon black, the ethanol solution, and the γ-glycidyloxypropyltrimethoxysilane is 100:1100:14, heat up, mix evenly, react at 60°C for 5 hours, and after the reaction is completed, cool, centrifuge, wash with anhydrous ethanol, and dry in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black;

[0065] Step 2, using carboxylated graphene to be ultrasonically dispersed in N,N-dimethylformamide, after being evenly dispersed, adding epoxidized white carbon black, heating, adding catalyst p-toluenesulfonic acid, wherein the mass ratio of carboxylated graphene, N,N-dimethylformamide, epoxidized white carbon black, and catalyst p-toluenesulfonic acid is 21:4200:100:0.7, stirring and mixing, reacting at 105°C for 6 hours, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying in a vacuum drying oven at 60°C for 12 hours to obtain a modified filler;

[0066] Step 3: Evenly mix the hydrogen-containing silicone oil, modified filler and thickener carboxymethyl cellulose, heat to 45°C, stir for 1.5h, add an emulsifier, the emulsifier is composed of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 25min, then add deionized water, wherein the mass ratio of hydrogen-containing silicone oil, modified filler, thickener, emulsifier and deionized water is 92:8:0.45:8:130, stir for 40min, cool, and obtain an emulsion defoamer.

[0067] Comparative Example 2

[0068] A method for preparing an emulsion defoamer comprises the following steps:

[0069] Step 1, ultrasonically disperse the white carbon black in a 95% ethanol aqueous solution, adjust the pH to 3.5 with an acetic acid solution, and then add γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of the white carbon black, the ethanol solution, and the γ-glycidyloxypropyltrimethoxysilane is 100:1100:14, heat up, mix evenly, react at 60°C for 5 hours, and after the reaction is completed, cool, centrifuge, wash with anhydrous ethanol, and dry in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black;

[0070] Step 2, ultrasonically disperse the epoxidized silica in toluene, mix evenly, add 9-octadecene-1,12-diol, wherein the mass ratio of the epoxidized silica, toluene, and 9-octadecene-1,12-diol is 100:1400:95, heat up, mix, react at 110°C, and react for 14 hours. After the reaction is completed, filter, wash with methanol, and dry in a drying oven at 60°C for 24 hours to obtain modified silica;

[0071] Step 3, using carboxylated graphene to be ultrasonically dispersed in N,N-dimethylformamide, after being evenly dispersed, adding modified white carbon black, heating, adding catalyst p-toluenesulfonic acid, wherein the mass ratio of carboxylated graphene, N,N-dimethylformamide, modified white carbon black, and catalyst p-toluenesulfonic acid is 21:4200:100:0.7, stirring and mixing, reacting at 105°C for 6 hours, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying in a vacuum drying oven at 60°C for 12 hours to obtain a fatty alcohol modified filler;

[0072] Step 4: Evenly mix the hydrogenated silicone oil, fatty alcohol-modified filler and thickener carboxymethyl cellulose, heat to 45°C, stir for 1.5 hours, add an emulsifier, the emulsifier is composed of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 25 minutes, and then add deionized water, wherein the mass ratio of hydrogenated silicone oil, fatty alcohol-modified filler, thickener, emulsifier and deionized water is 92:8:0.45:8:130, stir for 40 minutes, cool, and obtain an emulsion defoamer.

[0073] Comparative Example 3

[0074] A method for preparing an emulsion defoamer comprises the following steps:

[0075] Step 1, ultrasonically disperse the white carbon black in a 95% ethanol aqueous solution, adjust the pH to 3.5 with an acetic acid solution, and then add γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of the white carbon black, the ethanol solution, and the γ-glycidyloxypropyltrimethoxysilane is 100:1100:14, heat up, mix evenly, react at 60°C for 5 hours, and after the reaction is completed, cool, centrifuge, wash with anhydrous ethanol, and dry in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black;

[0076] Step 2: Evenly mix the hydrogenated silicone oil, epoxidized silica, carboxylated graphene and thickener carboxymethyl cellulose, heat to 45°C, stir for 1.5h, add an emulsifier, the emulsifier is composed of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 25min, and then add deionized water, wherein the mass ratio of hydrogenated silicone oil, epoxidized silica, carboxylated graphene, thickener, emulsifier and deionized water is 92:6.6:1.4:0.45:8:130, stir for 40min, cool and obtain an emulsion defoamer.

[0077] Comparative Example 4

[0078] A method for preparing an emulsion defoamer comprises the following steps:

[0079] Step 1: Evenly mix hydrogenated silicone oil, white carbon black, graphene oxide and thickener carboxymethyl cellulose, heat to 45°C, stir for 1.5h, add emulsifier, the emulsifier is composed of Span 80 and Tween 80 in a mass ratio of 3:2, stir for 25min, then add deionized water, wherein the mass ratio of hydrogenated silicone oil, white carbon black, graphene oxide, thickener, emulsifier and deionized water is 92:6.6:1.4:0.45:8:130, stir for 40min, cool and obtain an emulsion defoamer.

[0080] The white carbon black in the embodiments and comparative examples of the present invention is fumed white carbon black with a particle size of 7-40 nm, purchased from Guangzhou Jibisheng Technology Co., Ltd., hydrogen-containing silicone oil was purchased from Tianjin Yimei Fine Chemical Factory (hydrogen base mass fraction 0.2-1.0%, viscosity 10-30 mPa·s at 25°C), and the CAS number of 9-octadecene-1,12-diol is 1577-55-5; other undisclosed reagents are all commercially available.

[0081] The emulsion defoamers prepared in Examples 1-4 and Comparative Examples 1-4 were tested accordingly, and the test methods and test results are as follows:

[0082] (1) Defoaming performance test: The test standard adopts GB / T26527-2011, and the defoaming performance test condition is to shake the measuring cylinder vertically up and down 10 times;

[0083] (2) Antifoaming performance test: A lubricating oil foam characteristic tester that meets the test requirements of GB / T 12579 was used, and the constant temperature water bath temperature of the instrument was set to 25°C and 80°C, respectively, and the test gas flow rate was 100 mL / min. 100 g of the foaming liquid was weighed, and 0.1 g of the defoaming agent prepared in Examples 1-4 and Comparative Examples 1-4 was weighed, respectively, and added to the foaming liquid, stirred evenly, and then poured into a clean bubbler measuring cylinder, and the temperature was kept constant at 25°C and 80°C, respectively. The flow pump was turned on and the test was started. The foam volume (mL) after 30 minutes of air blowing was recorded. The antifoaming performance was represented by the foam volume corresponding to 30 minutes of air blowing;

[0084] (3) Stability test: 15 mL of the emulsion defoamer prepared in Examples 1-4 and Comparative Examples 1-4 were respectively placed in centrifuge tubes and centrifuged in a high-speed centrifuge at a speed of 3000 r / min. The stability was observed by continuous centrifugation for 30 min.

[0085] The above test results are shown in Table 1:

[0086] Table 1

[0087] Test items Defoaming performance(s) Antifoam performance (mL) stability Example 1 8.6 321 Unstratified Example 2 6.9 297 Unstratified Example 3 5.7 285 Unstratified Example 4 7.3 310 Unstratified Comparative Example 1 14.1 345 More obvious stratification Comparative Example 2 11.7 332 Slight delamination Comparative Example 3 15.2 353 More obvious stratification Comparative Example 4 16.4 362 Obvious stratification

[0088] According to the test results of Table 1, it can be seen that the defoamer corresponding to Examples 1-4 is continuously centrifuged for 30min without stratification, has excellent stability, and has excellent defoaming performance and foam suppression performance, rapid defoaming, and good foam suppression effect. In Comparative Example 1, fatty alcohol is not introduced, and epoxidized white carbon black and carboxylated graphene are directly mixed to obtain a modified filler, and then hydrogenated silicone oil, modified filler, thickener, and emulsifier are mixed, the dispersibility between the raw materials deteriorates, the comprehensive performance is greatly reduced, the stability is poor, and more obvious stratification occurs, the defoaming performance and foam suppression performance are reduced, the defoaming time is 14.1s, and the foam suppression performance is 345mL. In Comparative Example 2, hydrogenated silicone oil and fatty alcohol modified filler are directly mixed, the comprehensive performance is reduced, the defoaming time is 11.7s, the foam suppression performance is 332mL, the stability is reduced, and slight stratification occurs. In Comparative Example 3, epoxidized silica and carboxylated graphene were used instead of fatty alcohol modified fillers, and hydrogen-containing silicone oil was mixed and emulsified with epoxidized silica, carboxylated graphene, thickener, emulsifier, and deionized water, and the defoaming and anti-foaming properties became worse, and obvious stratification occurred. In Comparative Example 4, silica and graphene oxide were not modified, and were directly added to the defoamer system, and the comprehensive performance was greatly reduced, the defoaming time was 16.4s, the anti-foaming performance was 362mL, and obvious stratification occurred.

[0089] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that all equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for preparing an emulsion defoamer with excellent stability, characterized in that: The steps include: Step 1, ultrasonically dispersing white carbon black in an ethanol solution, adjusting the pH to 3-4, adding γ-glycidyloxypropyltrimethoxysilane, heating, mixing evenly, reacting, cooling after the reaction, centrifuging, washing, and drying in a drying oven at 80°C for 24 hours to obtain epoxidized white carbon black; Step 2, ultrasonically dispersing the epoxidized silica in toluene, mixing evenly, adding 9-octadecene-1,12-diol, heating, mixing, reacting, and after the reaction is completed, filtering, washing, and drying in a drying oven at 60° C. for 24 hours to obtain modified silica; Step 3: Ultrasonic dispersion of carboxylated graphene in N,N-dimethylformamide, uniform dispersion, adding modified white carbon black, heating, adding a catalyst, stirring and mixing, reacting, and after the reaction is completed, filtering, washing, and drying in a vacuum drying oven at 60° C. for 12 hours to obtain a fatty alcohol modified filler; Step 4: mixing the hydrogen-containing silicone oil, the fatty alcohol-modified filler and chloroplatinic acid, heating them in a nitrogen atmosphere, reacting them, and obtaining modified organosilicon after the reaction is completed; Step 5: Evenly mix the modified silicone and thickener, heat to 40-50°C, stir for 1-2h, add the emulsifier, stir for 15-30min, then add deionized water, stir for 30-45min, and cool to obtain an emulsion defoamer with excellent stability.

2. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: In the step 1, the mass ratio of white carbon black, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:950-1200:12-15, the reaction temperature is 55-65° C., and the reaction time is 4-6 hours.

3. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: In the step 2, the mass ratio of epoxidized white carbon black, toluene and 9-octadecene-1,12-diol is 100:1200-1500:85-102.

4. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: The reaction temperature in step 2 is 105-115° C., and the reaction time is 12-15 h.

5. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: In the step three, the mass ratio of carboxylated graphene, N,N-dimethylformamide, modified white carbon black and catalyst is 15-25:3500-4800:100:0.5-0.8, the reaction temperature is 100-110° C., and the reaction time is 5-8 hours.

6. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: In the step 4, the mass ratio of hydrogen silicone oil, fatty alcohol modified filler and chloroplatinic acid is 100:6-10:0.2-0.4, the reaction temperature is 95-130° C., and the reaction time is 4-6 hours.

7. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: In the step 5, the mass ratio of modified silicone, thickener, emulsifier and deionized water is 100:0.3-0.5:6-9:105-140.

8. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: The thickener in step 5 includes one or more of carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

9. The method for preparing an emulsion defoamer with excellent stability according to claim 1, characterized in that: In the step 5, the emulsifier is composed of Span 80 and Tween 80 in a mass ratio of 3:

2.

10. An emulsion-type defoamer with excellent stability prepared by the method for preparing an emulsion-type defoamer with excellent stability according to any one of claims 1 to 9.