Preparation method of organic silicon emulsion defoaming agent applied to foam treatment of alkaline degreasing agent

Abstract

The invention relates to the technical field of chemical additives, in particular to a preparation method of a low-concentration organic silicon emulsion defoaming agent applied to foam treatment of an alkaline degreasing agent. The high-temperature-resistant silicone rubber comprises the following raw material components: polyether modified siloxane, silicon polyether emulsion, dimethyl silicone grease, low-hydrogen-content silicone oil, allyl polyoxyethylene polyoxypropylene ether, trihydroxy polyoxypropylene ether, methacrylate and a chloroplatinic acid catalyst. The preparation method comprises the following steps: enabling low-hydrogen-content silicone oil and an emulsifier AEO-3 to react with allyl polyoxyethylene polyoxypropylene ether and methacrylate under the action of a catalyst to generate polyether co-modified silicone oil; secondly, reacting dodecyl dimethyl tertiary amine, trihydroxy polyoxypropylene ether and MTES under the action of a catalyst to generate polyether modified silane; mixing and stirring the silicone oil silane coupling liquid and other residual components, and then adding the acrylic acid type alkali swelling thickening agent to prepare the final low-concentration organic silicon emulsion defoaming agent. The defoaming agent has excellent defoaming performance and stability, and is suitable for foam treatment of an alkaline degreasing agent.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical additives, and in particular to a method for preparing a low-concentration silicone emulsion defoamer for use in alkaline degreasing agent foam treatment. The defoamer exhibits excellent defoaming performance and stability through a specific component ratio and a unique preparation process, and is particularly suitable for degreasing agent foam control in an alkaline environment. Background Art

[0002] Before metal chemical treatment, electroplating and coating, degreasing agents should be used to remove grease and mineral oil on the metal surface. Degreasing agents with surfactants as the main formula will not damage the texture of metal products when cleaning the metal surface, and a small amount of degreasing agents can emulsify and disperse a large amount of grease, so that the oil stains are easily removed from the metal surface. They are an ideal type of metal cleaning agent. Degreasing agents with surfactants in the formula mainly rely on their emulsification effect to remove oil stains on the metal surface. It is best to use surfactants with a lower HLB value. However, such substances are weakly water-soluble and difficult to rinse, and often leave an adsorption film on the surface of the washed object. When the amount of oil stains is small, degreasing cleaning agents mainly based on alkalis supplemented with surfactants can reduce the cost of cleaning agents. The surfactants added to the degreasing agent are the main cause of foaming. If the concentration of surfactants in the formula is unbalanced, or too many surfactants are added to the formula, it will cause excessive foam in the degreasing agent. If these foams are not removed in time, they will have a serious impact on the quality of metal products. The mainstream defoamers on the market, such as Dow Corning DOWSIL AFE-7820 emulsion defoamer, have gradually failed to meet the growing process requirements of metal products. Therefore, it is urgent to develop new defoamers with higher defoaming efficiency and better effects for alkaline degreasing agent foam treatment. Summary of the invention

[0003] The purpose of the present invention is to provide a low-concentration silicone emulsion defoamer, which can effectively inhibit the generation of foam under alkaline conditions and has good stability and wetting properties. The low-dose defoamer can quickly eliminate the foam generated by the alkaline degreasing agent during the production and application process, and effectively inhibit the large-scale generation of foam in the subsequent process, thereby achieving effective control of the foam. The defoamer has good water solubility and a low silicone content in the working fluid.

[0004] The technical solution of the present invention is as follows: A method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment, characterized in that the mass formula of its raw material components is: Polyether modified siloxane 15-18 parts Silicone polyether emulsion 25-30 parts 3-5 parts of dimethyl silicone grease 50-55 parts of low hydrogen silicone oil Allyl polyoxyethylene polyoxypropylene ether 5-8 parts 3-5 parts of trihydroxy polyoxypropylene ether Methacrylate 5-8 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 5-8 parts Emulsifier AEO-3 1-2 parts 1-2 parts of dodecyl dimethyl tertiary amine 1-2 parts of acrylic acid type alkali swelling thickener Each component totals 100 parts; The preparation method is as follows: S1: Add low hydrogen silicone oil and emulsifier AEO-3 into a reaction vessel, heat to 75-80°C, stir, add chloroplatinic acid catalyst, heat to 85-90°C, introduce nitrogen protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate in a continuous feeding manner, stir and react for 1.5-2 hours to obtain polyether co-modified silicone oil; S2: dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether are mixed, heated to 40-50°C, stirred, and then methyl triethoxysilane (MTES) is added, chloroplatinic acid catalyst is added, the temperature is raised to 100-105°C, and stirred for reaction for 4-5 hours to obtain polyether modified silane; S3: Stirring the polyether co-modified silicone oil and polyether modified silane for 30-45 minutes to mix evenly to obtain a silicone oil-silane coupling liquid; S4: Mix silicone oil silane coupling liquid, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease and emulsifier AEO-3, stir for 3-4 hours, then add acrylic acid type alkali swelling thickener and mix evenly to obtain.

[0005] A method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment, characterized in that the mass formula of its raw material components is: 15 parts of polyether modified siloxane Silicone polyether emulsion 25 parts 3 parts dimethyl silicone 50 parts of low hydrogen silicone oil Allyl polyoxyethylene polyoxypropylene ether 5 parts 3 parts of trihydroxy polyoxypropylene ether Methacrylate 5 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 5 parts Emulsifier AEO-3 1 part 1 part of dodecyl dimethyl tertiary amine 1 part of acrylic acid type alkali swelling thickener.

[0006] The method for preparing a silicone emulsion defoamer for alkaline degreasing agent foam treatment is characterized in that the mass formula of its raw material components is: 18 parts of polyether modified siloxane Silicone polyether emulsion 30 parts 5 parts of dimethyl silicone grease 55 parts of low hydrogen silicone oil 8 parts of allyl polyoxyethylene polyoxypropylene ether 5 parts of trihydroxy polyoxypropylene ether Methacrylate 8 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 8 parts Emulsifier AEO-3 2 parts 2 parts of dodecyl dimethyl tertiary amine 2 parts of acrylic acid type alkali swelling thickener.

[0007] The method for preparing a silicone emulsion defoamer for alkaline degreasing agent foam treatment is characterized in that the mass formula of its raw material components is: 16 parts of polyether modified siloxane Silicone polyether emulsion 28 parts 4 parts dimethyl silicone grease 52 parts of low hydrogen silicone oil Allyl polyoxyethylene polyoxypropylene ether 6 parts 4 parts of trihydroxy polyoxypropylene ether Methacrylate 6 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 6 parts Emulsifier AEO-3 1 part 2 parts of dodecyl dimethyl tertiary amine 2 parts of acrylic acid type alkali swelling thickener.

[0008] The method for preparing a silicone emulsion defoamer used in alkaline degreasing agent foam treatment is characterized in that the preparation method is as follows: S1: Add low hydrogen silicone oil and emulsifier AEO-3 into a reaction vessel, heat to 80°C, stir, add chloroplatinic acid catalyst, heat to 90°C, introduce nitrogen protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate in a continuous feeding manner, stir and react for 1.5 hours to obtain polyether co-modified silicone oil; S2: dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether are mixed, heated to 50°C, stirred, and then methyl triethoxysilane (MTES) is added, chloroplatinic acid catalyst is added, the temperature is raised to 100°C, and stirred for reaction for 4 hours to obtain polyether modified silane; S3: Stir the polyether co-modified silicone oil, polyether modified silane and silane coupling agent KH-560 for 45 minutes to mix them evenly to obtain a silicone oil silane coupling liquid; S4: Mix silicone oil silane coupling liquid, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease and emulsifier AEO-3, stir for 3 hours, then add acrylic acid type alkali swelling thickener and mix evenly to obtain.

[0009] Hydrosilylation reaction of low hydrogen silicone oil with allyl polyoxyethylene polyoxypropylene ether and methacrylate: Under the action of chloroplatinic acid catalyst, the Si-H bond in low hydrogen silicone oil reacts with the unsaturated bond (such as C=C) in allyl polyoxyethylene polyoxypropylene ether and methacrylate to form modified silicone oil containing polyether segments. This modified silicone oil not only has excellent defoaming performance, but also improves its dispersibility and stability in water-based systems due to the introduction of polyether segments.

[0010] Nitrogen protection: The introduction of nitrogen can prevent the interference of oxygen during the reaction process, ensuring the smooth progress of the reaction and the purity of the product.

[0011] Condensation reaction of methyltriethoxysilane (MTES) and trihydroxy polyoxypropylene ether: Under the action of chloroplatinic acid catalyst, the ethoxy group of MTES and the hydroxyl group of trihydroxy polyoxypropylene ether undergo condensation reaction to generate polyether modified silane. This step further enriches the chemical structure of the defoamer and enhances its versatility.

[0012] The polyether co-modified silicone oil, polyether modified silane and silane coupling agent KH-560 are physically mixed, and the components are evenly dispersed by stirring to form a silicone oil silane coupling liquid. This step promotes the interaction between different components and lays the foundation for the subsequent preparation of a stable emulsion.

[0013] The silicone oil silane coupling liquid is mixed with other components (such as polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease, emulsifier AEO-3), and each component is fully emulsified by stirring to form a stable emulsion. Emulsifier AEO-3 plays a key role in this process, which reduces the tension of the oil-water interface and promotes the stable formation of the emulsion.

[0014] After adding the acrylic acid type alkali swelling thickener, the viscosity of the emulsion system increases, further improving the stability and durability of the emulsion. At the same time, the thickener can also maintain good performance in an alkaline environment, meeting the requirements of alkaline degreasing agent foam treatment.

[0015] The components of the defoamer of the present invention achieve synergistic effects through chemical reactions, physical mixing and nano-effects. The introduction of polyether segments improves the hydrophilicity and dispersibility of the defoamer; the hydrosilylation reaction and condensation reaction enrich the chemical structure of the defoamer; and the addition of emulsifiers and thickeners ensures the stability and durability of the emulsion. The combined effect of these factors enables the defoamer of the present invention to exhibit excellent performance in the foam treatment of alkaline degreasing agents.

[0016] Advantages of the present invention: 1. Excellent defoaming performance The low-concentration silicone emulsion defoamer of the present invention is specially designed for alkaline degreasing agent foam treatment, and can effectively perform rapid defoaming and long-lasting foam suppression on the foam generated in an alkaline environment. The defoaming ability of the defoamer is significantly improved through the synergistic effect of multiple components such as polyether-modified siloxane, silicone polyether emulsion, and dimethyl silicone grease. These components are excellent in reducing liquid surface tension and destroying foam stability, and can quickly eliminate foam and prevent its regeneration.

[0017] 2. Good stability Due to the use of high temperature resistant, acid and alkali resistant raw materials, such as low hydrogen silicone oil, methyl triethoxysilane, etc., the defoamer of the present invention can still maintain stable performance in the strong alkaline environment of the alkaline degreasing agent and is not easy to decompose or fail. The uniformity and stability of the emulsion are ensured through reasonable formula design and preparation process. The addition of emulsifier AEO-3 effectively reduces the tension of the oil-water interface and promotes the stable formation of the emulsion; the addition of acrylic acid type alkali swelling thickener further improves the viscosity and stability of the emulsion.

[0018] 3. Wide applicability It can be used to treat the foam generated by alkaline degreasing agents in the production process of metal chemical treatment, electroplating and coating. The experimental results show that the low-concentration organosilicon emulsion defoamer in the present invention has a defoaming rate increased by 53.76 parts compared with the organosilicon emulsion defoamer on the market, and the average time for inhibiting foam growth is extended by 173.28 parts. DETAILED DESCRIPTION

[0019] A low-concentration silicone emulsion defoamer used for alkaline degreasing agent foam treatment, weighing the following raw material components: Polyether modified siloxane 180g Silicone polyether emulsion 260g 35g dimethyl silicone Low hydrogen silicone oil 550g Allyl polyoxyethylene polyoxypropylene ether 50g 35g trihydroxy polyoxypropylene ether Methacrylate 50g Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 60 g Emulsifier AEO-3 20g 20g dodecyl dimethyl tertiary amine Acrylic acid type alkali swelling thickener 10g The preparation method is as follows: S1: Add low hydrogen silicone oil and part of the emulsifier AEO-3 to the reaction vessel, heat to 75-80°C, stir, add chloroplatinic acid catalyst, heat to 85-90°C, introduce nitrogen protection, and add allyl polyoxyethylene polyoxypropylene ether and methacrylate in a continuous feeding manner, stir and react for 1.5-2 hours to obtain polyether co-modified silicone oil; low hydrogen silicone oil (an organic silicon compound containing Si-H bonds) and emulsifier AEO-3 (a non-ionic surfactant) are mixed in the reaction vessel. The role of the emulsifier is to help form a stable emulsion and reduce the tension of the oil-water interface in subsequent reactions. Allyl polyoxyethylene polyoxypropylene ether and methacrylate are added in a continuous feeding manner. Both compounds contain unsaturated bonds (C=C double bonds) and can undergo silylation reaction with the Si-H bonds in the low hydrogen silicone oil. By continuously adding, the reactants can be ensured to be evenly distributed in the reaction system, promoting the uniform progress of the reaction. The entire reaction process is mainly a hydrosilylation reaction, in which low-hydrogen silicone oil provides Si-H bonds as hydrides, and allyl polyoxyethylene polyoxypropylene ether and methacrylate provide C=C double bonds as unsaturated compounds. Under the action of chloroplatinic acid catalyst, these reactants undergo addition reaction under appropriate temperature and stirring conditions to generate modified silicone oil with polyether segments. This modified silicone oil not only retains the excellent properties of organosilicon compounds, but also improves its dispersibility and stability in aqueous systems by introducing polyether segments.

[0020] S2: dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether are mixed, heated to 40-50°C, stirred, and then methyl triethoxysilane (MTES) is added, chloroplatinic acid catalyst is added, the temperature is raised to 100-105°C, and stirred for reaction for 4-5 hours to obtain polyether modified silane; methyl triethoxysilane (MTES) is hydrolyzed under the action of chloroplatinic acid catalyst to generate silanol, and then the silanol undergoes condensation reaction with the hydroxyl group in trihydroxy polyoxypropylene ether to generate polyether modified silane.

[0021] S3: Stirring the polyether co-modified silicone oil and polyether modified silane for 30-45 minutes to mix evenly to obtain a silicone oil-silane coupling liquid; S4: Mix silicone oil silane coupling liquid, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease, and the remaining emulsifier AEO-3, stir for 3-4 hours, and then add acrylic acid type alkali swelling thickener and mix evenly to obtain. Adding acrylic acid type alkali swelling thickener, this thickener can swell under alkaline conditions and increase the viscosity of the system, thereby improving the stability and fluidity of the emulsion. Emulsifier AEO-3 helps reduce the tension of the oil-water interface and promotes the dispersion and emulsification of organosilicon compounds in water. In addition, the addition of acrylic acid type alkali swelling thickener further improves the stability and fluidity of the emulsion.

[0022] Sample detection of the present invention: Detection method: Add 200ml of degreasing agent stock solution to the circulating spray device, start running, and add 0.1ml of defoamer when the foam rises to the scale height (450ml in this experiment). Timing and observing whether the foam has a downward trend or stays at a certain height and no longer rises, record it as the defoaming time. When the foam disappears to a certain interface and no longer rises, and when the foam height returns to the scale, record it as the foam suppression time. Both the market defoamer and the test defoamer are diluted five times with tap water. The market defoamer is a competitive defoamer used on-site by Adovi, and the test defoamer is a low-concentration silicone emulsion defoamer provided by the present invention.

[0023] .

Claims

1. A method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment, characterized in that: The quality formula of its raw material components is: Polyether modified siloxane 15-18 parts Silicone polyether emulsion 25-30 parts 3-5 parts of dimethyl silicone grease 50-55 parts of low hydrogen silicone oil Allyl polyoxyethylene polyoxypropylene ether 5-8 parts 3-5 parts of trihydroxy polyoxypropylene ether Methacrylate 5-8 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 5-8 parts Emulsifier AEO-3 1-2 parts 1-2 parts of dodecyl dimethyl tertiary amine 1-2 parts of acrylic acid type alkali swelling thickener The preparation method is as follows: S1: Add low hydrogen silicone oil and emulsifier AEO-3 into a reaction vessel, heat to 75-80°C, stir, add chloroplatinic acid catalyst, heat to 85-90°C, introduce nitrogen protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate in a continuous feeding manner, stir and react for 1.5-2 hours to obtain polyether co-modified silicone oil; S2: dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether are mixed, heated to 40-50°C, stirred, and then methyl triethoxysilane (MTES) is added, chloroplatinic acid catalyst is added, the temperature is raised to 100-105°C, and stirred for reaction for 4-5 hours to obtain polyether modified silane; S3: Stir the polyether co-modified silicone oil, polyether modified silane and silane coupling agent KH-560 for 30-45 minutes to mix evenly to obtain silicone oil silane coupling liquid; S4: Mix silicone oil silane coupling liquid, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease and emulsifier AEO-3, stir for 3-4 hours, then add acrylic acid type alkali swelling thickener and mix evenly to obtain.

2. The method for preparing a silicone emulsion defoamer for use in alkaline degreasing agent foam treatment according to claim 1, characterized in that: The quality formula of its raw material components is: 15 parts of polyether modified siloxane Silicone polyether emulsion 25 parts 3 parts dimethyl silicone 50 parts of low hydrogen silicone oil Allyl polyoxyethylene polyoxypropylene ether 5 parts 3 parts of trihydroxy polyoxypropylene ether Methacrylate 5 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 5 parts Emulsifier AEO-3 1 part 1 part of dodecyl dimethyl tertiary amine 1 part of acrylic acid type alkali swelling thickener.

3. The method for preparing a silicone emulsion defoamer for use in alkaline degreasing agent foam treatment according to claim 1, characterized in that: The quality formula of its raw material components is: 18 parts of polyether modified siloxane Silicone polyether emulsion 30 parts 5 parts of dimethyl silicone grease 55 parts of low hydrogen silicone oil 8 parts of allyl polyoxyethylene polyoxypropylene ether 5 parts of trihydroxy polyoxypropylene ether Methacrylate 8 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 8 parts Emulsifier AEO-3 2 parts 2 parts of dodecyl dimethyl tertiary amine 2 parts of acrylic acid type alkali swelling thickener.

4. The method for preparing a silicone emulsion defoamer for use in alkaline degreasing agent foam treatment according to claim 1, characterized in that: The quality formula of its raw material components is: 16 parts of polyether modified siloxane Silicone polyether emulsion 28 parts 4 parts dimethyl silicone grease 52 parts of low hydrogen silicone oil 6 parts of allyl polyoxyethylene polyoxypropylene ether 4 parts of trihydroxy polyoxypropylene ether Methacrylate 6 parts Chloroplatinic acid catalyst Methyltriethoxysilane (MTES) 6 parts Emulsifier AEO-3 1 part 2 parts of dodecyl dimethyl tertiary amine 2 parts of acrylic acid type alkali swelling thickener.

5. The method for preparing a silicone emulsion defoamer for use in alkaline degreasing agent foam treatment according to claim 1, characterized in that: The preparation method is as follows: S1: Add low hydrogen silicone oil and emulsifier AEO-3 into a reaction vessel, heat to 80°C, stir, add chloroplatinic acid catalyst, heat to 90°C, introduce nitrogen protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate in a continuous feeding manner, stir and react for 1.5 hours to obtain polyether co-modified silicone oil; S2: dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether are mixed, heated to 50°C, stirred, and then methyl triethoxysilane (MTES) is added, chloroplatinic acid catalyst is added, the temperature is raised to 100°C, and stirred for reaction for 4 hours to obtain polyether modified silane; S3: Stirring the polyether co-modified silicone oil and polyether modified silane for 45 minutes to mix evenly to obtain a silicone oil-silane coupling liquid; S4: Mix silicone oil silane coupling liquid, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease and emulsifier AEO-3, stir for 3 hours, then add acrylic acid type alkali swelling thickener and mix evenly to obtain.