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

Abstract

This invention relates to the field of chemical additives technology, specifically a method for preparing a low-concentration silicone emulsion defoamer for use in alkaline degreasing agent foam treatment. Its raw material components include polyether-modified siloxane, silicone polyether emulsion, dimethyl silicone grease, low-hydrogen silicone oil, allyl polyoxyethylene polyoxypropylene ether, trihydroxy polyoxypropylene ether, methacrylate, and chloroplatinic acid catalyst. The low-hydrogen silicone oil reacts with the emulsifier AEO-3, allyl polyoxyethylene polyoxypropylene ether, and methacrylate under the action of a catalyst to generate polyether co-modified silicone oil. Next, dodecyl dimethyl tertiary amine, trihydroxy polyoxypropylene ether, and MTES react under the action of a catalyst to generate polyether-modified silane. The silicone oil-silane coupling solution is mixed with the remaining components and stirred, and then an acrylic-type alkali-swelling thickener is added to obtain the final low-concentration silicone emulsion defoamer. This defoamer exhibits excellent defoaming performance and stability, and is suitable for foam treatment with alkaline degreasing agents.

Description

Technical Field

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

[0002] Before chemical treatment, electroplating, and coating of metals, degreasing agents are used to remove grease and mineral oil from the metal surface. Degreasing agents formulated primarily with surfactants clean metal surfaces without damaging the metal's texture. A small amount of degreasing agent can emulsify and disperse a large amount of grease, making it easier for the grease to detach from the metal surface, making it a relatively ideal type of metal cleaning agent. Degreasing agents containing surfactants rely mainly on their emulsifying effect to remove grease from metal surfaces; it is best to choose surfactants with low HLB values. However, these substances are poorly water-soluble, difficult to rinse, and often leave an adsorbed film on the surface of the cleaned object. Alkali-based degreasing cleaners, when the amount of grease is small, can reduce cleaning costs by using alkali as the main component supplemented with surfactants. The surfactants added to degreasing agents are the main cause of foaming. If the surfactant concentration in the formula is uneven, or if too much surfactant is added, excessive foaming will occur. If this foam is not removed promptly, it will seriously affect the quality of the metal products. Currently, mainstream defoamers on the market, such as Dow Corning DOWSIL AFE-7820 emulsion defoamer, are gradually failing to meet the growing processing demands of metal products. Therefore, there is an urgent need to develop new defoamers with higher defoaming efficiency and better performance for treating foams from alkaline degreasing agents. Summary of the Invention

[0003] The purpose of this invention is to provide a low-concentration silicone emulsion defoamer that effectively inhibits foam generation under alkaline conditions while exhibiting good stability and wetting properties. It can rapidly eliminate foam generated during the production and application of alkaline degreasing agents at low doses, and effectively inhibits excessive foam generation in subsequent processes, achieving effective foam control. It also possesses good water solubility and a low silicone content in the working solution.

[0004] The technical solution of the present invention is as follows:

[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 as follows:

[0006] 15-18 parts of polyether-modified siloxane

[0007] 25-30 parts of silicone polyether emulsion

[0008] 3-5 parts of dimethyl silicone grease

[0009] 50-55 parts of low-hydrogen silicone oil

[0010] 5-8 parts of allyl polyoxyethylene polyoxypropylene ether

[0011] 3-5 parts of trihydroxypolyoxypropylene ether

[0012] 5-8 parts of methacrylate

[0013] Appropriate amount of chloroplatinic acid catalyst

[0014] Methyltriethoxysilane (MTES) 5-8 parts

[0015] Emulsifier AEO-3 1-2 parts

[0016] 1-2 parts of dodecyl dimethyl tertiary amine

[0017] 1-2 parts of acrylic alkali-swellable thickener

[0018] A total of 100 portions of each component;

[0019] The preparation method is as follows:

[0020] S1: Add low-hydrogen silicone oil and emulsifier AEO-3 to a reaction vessel, heat to 75-80℃, stir, add chloroplatinic acid catalyst, raise the temperature to 85-90℃, purge with nitrogen for protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate by continuous feeding. Stir and react for 1.5-2 hours to obtain polyether co-modified silicone oil;

[0021] S2: Mix dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether, heat to 40-50℃, stir, then add methyltriethoxysilane (MTES), add chloroplatinic acid catalyst, heat to 100-105℃, stir and react for 4-5 hours; to obtain polyether modified silane;

[0022] S3: Mix polyether co-modified silicone oil and polyether modified silane for 30-45 minutes until homogeneous to obtain silicone oil-silane coupling solution;

[0023] S4: Mix silicone oil silane coupling solution, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease, and emulsifier AEO-3, stir for 3-4 hours, then add acrylic alkali swelling thickener and mix evenly to obtain the final product.

[0024] 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 as follows:

[0025] 15 parts of polyether-modified siloxane

[0026] 25 parts of silicone polyether emulsion

[0027] 3 parts dimethyl silicone grease

[0028] 50 parts of low-hydrogen silicone oil

[0029] 5 parts of allyl polyoxyethylene polyoxypropylene ether

[0030] 3 parts of trihydroxypolyoxypropylene ether

[0031] 5 parts methacrylate

[0032] Appropriate amount of chloroplatinic acid catalyst

[0033] 5 parts of methyltriethoxysilane (MTES)

[0034] 1 part of emulsifier AEO-3

[0035] 1 part of dodecyl dimethyl tertiary amine

[0036] One part of acrylic alkali-swellable thickener.

[0037] The method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment is characterized by the following mass formula of its raw material components:

[0038] 18 parts of polyether-modified siloxane

[0039] 30 parts of silicone polyether emulsion

[0040] 5 parts dimethyl silicone grease

[0041] 55 parts of low-hydrogen silicone oil

[0042] 8 parts of allyl polyoxyethylene polyoxypropylene ether

[0043] 5 parts of trihydroxypolyoxypropylene ether

[0044] 8 parts of methacrylate

[0045] Appropriate amount of chloroplatinic acid catalyst

[0046] 8 parts of methyltriethoxysilane (MTES)

[0047] Emulsifier AEO-3 2 parts

[0048] 2 parts of dodecyl dimethyl tertiary amine

[0049] Two parts of acrylic-based alkali-swellable thickener.

[0050] The method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment is characterized by the following mass formula of its raw material components:

[0051] 16 parts of polyether-modified siloxane

[0052] 28 parts of silicone polyether emulsion

[0053] 4 parts dimethyl silicone grease

[0054] 52 parts of low-hydrogen silicone oil

[0055] 6 parts of allyl polyoxyethylene polyoxypropylene ether

[0056] 4 parts of trihydroxypolyoxypropylene ether

[0057] 6 parts of methacrylate

[0058] Appropriate amount of chloroplatinic acid catalyst

[0059] 6 parts of methyltriethoxysilane (MTES)

[0060] 1 part of emulsifier AEO-3

[0061] 2 parts of dodecyl dimethyl tertiary amine

[0062] Two parts of acrylic-based alkali-swellable thickener.

[0063] The method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment is characterized by the following preparation method:

[0064] S1: Add low-hydrogen silicone oil and emulsifier AEO-3 to a reaction vessel, heat to 80°C, stir, add chloroplatinic acid catalyst, raise the temperature to 90°C, purge with nitrogen for protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate by continuous feeding. Stir and react for 1.5 hours to obtain polyether co-modified silicone oil.

[0065] S2: Dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether are mixed, heated to 50°C, stirred, and then methyltriethoxysilane (MTES) is added. Chloroplatinic acid catalyst is added, the temperature is raised to 100°C, and the reaction is stirred for 4 hours to obtain polyether modified silane;

[0066] S3: Mix polyether co-modified silicone oil, polyether modified silane, and silane coupling agent KH-560 for 45 minutes until homogeneous to obtain silicone oil-silane coupling solution;

[0067] S4: Mix silicone oil silane coupling solution, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease, and emulsifier AEO-3, stir for 3 hours, then add acrylic alkali swelling thickener and mix evenly to obtain the final product.

[0068] Hydrosilylation reaction of low-hydrogen silicone oil with allyl polyoxyethylene polyoxypropylene ether and methacrylate: Under the action of chloroplatinic acid catalyst, the Si-H bonds in the low-hydrogen silicone oil undergo hydrosilylation reaction with the unsaturated bonds (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 properties, but also improves its dispersibility and stability in aqueous systems due to the introduction of polyether segments.

[0069] Nitrogen protection: Introducing nitrogen can prevent interference from oxygen during the reaction, ensuring the smooth progress of the reaction and the purity of the product.

[0070] Condensation reaction of methyltriethoxysilane (MTES) with trihydroxy polyoxypropylene ether: Under the catalysis of chloroplatinic acid, the ethoxy group of MTES condenses with the hydroxyl group of trihydroxy polyoxypropylene ether to generate polyether-modified silane. This step further enriches the chemical structure of the defoamer and enhances its multifunctionality.

[0071] Polyether-modified silicone oil, polyether-modified silane, and silane coupling agent KH-560 were physically mixed, and the components were uniformly dispersed by stirring to form a silicone oil-silane coupling liquid. This step promoted the interaction between the different components, laying the foundation for the subsequent preparation of a stable emulsion.

[0072] The silicone oil-silane coupling solution is mixed with other components (such as polyether-modified siloxane, silicone polyether emulsion, dimethyl silicone grease, and emulsifier AEO-3), and stirred to fully emulsify the components and form a stable emulsion. Emulsifier AEO-3 plays a crucial role in this process, reducing the tension at the oil-water interface and promoting the stable formation of the emulsion.

[0073] The addition of an acrylic-based alkali-swellable thickener increases the viscosity of the emulsion system, further improving its stability and durability. Simultaneously, this thickener maintains good performance in alkaline environments, meeting the requirements for foam treatment using alkaline degreasing agents.

[0074] The components of the defoamer of this 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; hydrosilylation and condensation reactions 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 this invention to exhibit excellent performance in alkaline degreasing agent foam treatment.

[0075] Advantages of this invention:

[0076] 1. Excellent defoaming performance

[0077] This invention relates to a low-concentration silicone emulsion defoamer specifically designed for alkaline degreasing agent foam treatment. It effectively and rapidly defoams and provides sustained foam suppression for foam generated in alkaline environments. Through the synergistic effect of multiple components, including polyether-modified siloxane, silicone polyether emulsion, and dimethyl silicone grease, the defoaming ability of the defoamer is significantly improved. These components excel at reducing liquid surface tension and disrupting foam stability, rapidly eliminating foam and preventing its regeneration.

[0078] 2. Good stability

[0079] Because it uses high-temperature and acid / alkali-resistant raw materials, such as low-hydrogen silicone oil and methyltriethoxysilane, the defoamer of this invention maintains stable performance even in the strongly alkaline environment of alkaline degreasing agents, and is not easily decomposed or ineffective. Through reasonable formulation design and preparation process, the uniformity and stability of the emulsion are ensured. The addition of emulsifier AEO-3 effectively reduces the tension at the oil-water interface, promoting stable emulsion formation; the addition of acrylic alkali-swelling thickener further improves the viscosity and stability of the emulsion.

[0080] 3. Wide applicability

[0081] This product can be used to treat foam generated by alkaline degreasing agents during metal chemical treatment, electroplating, and coating processes. Experimental results show that the low-concentration silicone emulsion defoamer of this invention increases the defoaming rate by 53.76 parts and extends the average time for inhibiting foam growth by 173.28 parts compared to commercially available silicone emulsion defoamers. Detailed Implementation

[0082] A low-concentration silicone emulsion defoamer for use in alkaline degreasing agent foam treatment, comprising the following raw material components:

[0083] 180g of polyether-modified siloxane

[0084] 260g of silicone polyether emulsion

[0085] 35g of dimethyl silicone grease

[0086] 550g of low-hydrogen silicone oil

[0087] 50g of allyl polyoxyethylene polyoxypropylene ether

[0088] 35g of trihydroxypolyoxypropylene ether

[0089] 50g of methacrylate

[0090] Appropriate amount of chloroplatinic acid catalyst

[0091] Methyltriethoxysilane (MTES) 60g

[0092] Emulsifier AEO-3 20g

[0093] 20 grams of dodecyl dimethyl tertiary amine

[0094] 10g of acrylic alkali-swellable thickener

[0095] The preparation method is as follows:

[0096] S1: Low-hydrogen silicone oil and a portion of the emulsifier AEO-3 are added to a reaction vessel, heated to 75-80℃, stirred, and chloroplatinic acid catalyst is added. The temperature is then raised to 85-90℃, and nitrogen gas is introduced for protection. Simultaneously, allyl polyoxyethylene polyoxypropylene ether and methacrylate are added via continuous feeding. The reaction is stirred for 1.5-2 hours to obtain polyether co-modified silicone oil. The low-hydrogen silicone oil (an organosilicon compound containing Si-H bonds) and emulsifier AEO-3 (a nonionic surfactant) are mixed in the reaction vessel. The emulsifier helps form a stable emulsion and reduces the tension at the oil-water interface in subsequent reactions. The continuous feeding of allyl polyoxyethylene polyoxypropylene ether and methacrylate, both containing unsaturated bonds (C=C double bonds), allows for hydrosilylation reactions with the Si-H bonds in the low-hydrogen silicone oil. This continuous feeding method ensures uniform distribution of the reactants in the reaction system, promoting a homogeneous reaction. The entire reaction process is primarily a hydrosilylation reaction, in which low-hydrogen silicone oil acts as a hydride providing Si-H bonds, while allyl polyoxyethylene polyoxypropylene ether and methacrylate act as unsaturated compounds providing C=C double bonds. Under the catalysis of chloroplatinic acid, these reactants undergo an addition reaction under appropriate temperature and stirring conditions to generate a 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.

[0097] S2: Mix dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether, heat to 40-50℃, stir, then add methyltriethoxysilane (MTES), add chloroplatinic acid catalyst, heat to 100-105℃, stir and react for 4-5 hours; to obtain polyether modified silane; methyltriethoxysilane (MTES) undergoes hydrolysis under the action of chloroplatinic acid catalyst to generate silanol, and then the silanol undergoes condensation reaction with the hydroxyl groups in trihydroxy polyoxypropylene ether to generate polyether modified silane.

[0098] S3: Mix polyether co-modified silicone oil and polyether modified silane for 30-45 minutes until homogeneous to obtain silicone oil-silane coupling solution;

[0099] S4: Mix the silicone oil-silane coupling solution, polyether-modified siloxane, silicone polyether emulsion, dimethyl silicone grease, and the remaining emulsifier AEO-3. Stir for 3-4 hours, then add the acrylic-type alkali-swelling thickener and mix thoroughly. The acrylic-type alkali-swelling thickener swells under alkaline conditions, increasing the viscosity of the system and thus improving the stability and flowability of the emulsion. Emulsifier AEO-3 helps reduce the tension at the oil-water interface, promoting the dispersion and emulsification of organosilicon compounds in water. Furthermore, the addition of the acrylic-type alkali-swelling thickener further improves the stability and flowability of the emulsion.

[0100] Sample testing of this invention:

[0101] Test method: 200ml of degreasing agent concentrate was added to the circulating spray device and started. When the foam rose to the marked height (450ml in this experiment), 0.1ml of defoamer was added. Timing was maintained and the foam was observed to see if it showed a downward trend or stopped rising at a certain height; this was recorded as the defoaming time. When the foam reached a certain level and stopped rising, and then returned to the marked height, this was recorded as the foam suppression time. Both the commercially available defoamer and the test defoamer were diluted five times with tap water. The commercially available defoamer was a competitor's product used on-site by Aidovi, and the test defoamer was the low-concentration silicone emulsion defoamer provided by this invention.

[0102] .

Claims

1. 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 as follows: 15-18 parts of polyether-modified siloxane 25-30 parts of silicone polyether emulsion 3-5 parts of dimethyl silicone grease 50-55 parts of low-hydrogen silicone oil 5-8 parts of allyl polyoxyethylene polyoxypropylene ether 3-5 parts of trihydroxypolyoxypropylene ether 5-8 parts of methacrylate Appropriate amount of 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 alkali-swellable thickener The preparation method is as follows: S1: Add low-hydrogen silicone oil and emulsifier AEO-3 to a reaction vessel, heat to 75-80℃, stir, add chloroplatinic acid catalyst, raise the temperature to 85-90℃, purge with nitrogen for protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate by continuous feeding. Stir and react for 1.5-2 hours to obtain polyether co-modified silicone oil; S2: Mix dodecyl dimethyl tertiary amine and trihydroxy polyoxypropylene ether, heat to 40-50℃, stir, then add methyltriethoxysilane (MTES), add chloroplatinic acid catalyst, heat to 100-105℃, stir and react for 4-5 hours; to obtain polyether modified silane; S3: Mix polyether co-modified silicone oil, polyether modified silane, and silane coupling agent KH-560 for 30-45 minutes until homogeneous to obtain silicone oil-silane coupling solution; S4: Mix silicone oil silane coupling solution, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease, and emulsifier AEO-3, stir for 3-4 hours, then add acrylic alkali swelling thickener and mix evenly to obtain the final product.

2. The method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment according to claim 1, characterized in that, The mass formula of its raw material components is as follows: 15 parts of polyether-modified siloxane 25 parts of silicone polyether emulsion 3 parts dimethyl silicone grease 50 parts of low-hydrogen silicone oil 5 parts of allyl polyoxyethylene polyoxypropylene ether 3 parts of trihydroxypolyoxypropylene ether 5 parts methacrylate Appropriate amount of chloroplatinic acid catalyst 5 parts of methyltriethoxysilane (MTES) 1 part of emulsifier AEO-3 1 part of dodecyl dimethyl tertiary amine One part of acrylic alkali-swellable thickener.

3. The method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment according to claim 1, characterized in that, The mass formula of its raw material components is as follows: 18 parts of polyether-modified siloxane 30 parts of silicone polyether emulsion 5 parts dimethyl silicone grease 55 parts of low-hydrogen silicone oil 8 parts of allyl polyoxyethylene polyoxypropylene ether 5 parts of trihydroxypolyoxypropylene ether 8 parts of methacrylate Appropriate amount of chloroplatinic acid catalyst 8 parts of methyltriethoxysilane (MTES) Emulsifier AEO-3 2 parts 2 parts of dodecyl dimethyl tertiary amine Two parts of acrylic-based alkali-swellable thickener.

4. The method for preparing an organosilicon emulsion defoamer for use in alkaline degreasing agent foam treatment according to claim 1, characterized in that, The mass formula of its raw material components is as follows: 16 parts of polyether-modified siloxane 28 parts of silicone polyether emulsion 4 parts dimethyl silicone grease 52 parts of low-hydrogen silicone oil 6 parts of allyl polyoxyethylene polyoxypropylene ether 4 parts of trihydroxypolyoxypropylene ether 6 parts of methacrylate Appropriate amount of chloroplatinic acid catalyst 6 parts of methyltriethoxysilane (MTES) 1 part of emulsifier AEO-3 2 parts of dodecyl dimethyl tertiary amine Two parts of acrylic-based alkali-swellable thickener.

5. The method for preparing an organosilicon 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 to a reaction vessel, heat to 80°C, stir, add chloroplatinic acid catalyst, raise the temperature to 90°C, purge with nitrogen for protection, and simultaneously add allyl polyoxyethylene polyoxypropylene ether and methacrylate by continuous feeding. 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 methyltriethoxysilane (MTES) is added. Chloroplatinic acid catalyst is added, the temperature is raised to 100°C, and the reaction is stirred for 4 hours to obtain polyether modified silane; S3: Mix polyether co-modified silicone oil and polyether modified silane for 45 minutes until homogeneous to obtain silicone oil-silane coupling solution; S4: Mix silicone oil silane coupling solution, polyether modified siloxane, silicone polyether emulsion, dimethyl silicone grease, and emulsifier AEO-3, stir for 3 hours, then add acrylic alkali swelling thickener and mix evenly to obtain the final product.