A low-foaming emulsifier based on disulfated rosin-polyether amine amide and a preparation method and application thereof

Abstract

This application relates to the technical field of surfactants, and in particular to a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, its preparation method, and its application; a method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide includes the following steps: reacting disproportionated rosin with thionyl chloride under the action of catalyst 1, then adding polyetheramine for further reaction, followed by alkali washing and separation to obtain a disproportionated rosin-polyetheramine amide intermediate; using the disproportionated rosin-polyetheramine amide intermediate as an initiator, reacting it with ethylene oxide under the action of catalyst 2 to obtain a low-foaming emulsifier; this application discloses a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, its preparation method, and its application. The prepared low-foaming emulsifier achieves three major functions: low foaming, good resistance to alkali hydrolysis, and good lubrication performance, simplifying the formulation structure and improving system compatibility and stability.

Description

Technical Field

[0001] This application relates to the technical field of surfactants, and in particular to a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, its preparation method, and its application. Background Technology

[0002] Semi-synthetic metalworking fluids, as a well-balanced industrial fluid, play an important role in modern machining. One of the core components of their formulation is the emulsifier, which is responsible for stably dispersing the oil phase in the aqueous phase. Traditional emulsifiers, such as fatty acid polyoxyethylene ether esters, while having good emulsifying properties, have significant drawbacks in practical applications: Foaming is a prominent issue: Under high pressure and high circulation rate processing conditions, surfactants containing linear polyoxyethylene structures are prone to generating a large amount of stable foam. Foam can reduce cooling efficiency, affect processing accuracy, and cause liquid tank overflow. To solve this problem, it is usually necessary to add defoamers, but defoamers may cause the system to become turbid or fail.

[0003] Poor resistance to alkali hydrolysis: To ensure rust prevention and antibacterial properties, the working fluid of semi-synthetic metalworking fluid is usually maintained in an alkaline state. Under these conditions, traditional ester-bonded nonionic surfactants are prone to hydrolysis, leading to molecular chain breakage, failure of emulsification function, decreased system stability, and shortened service life.

[0004] Single function: Traditional emulsifiers mainly provide emulsification, but their own lubrication is limited. The lubrication required by the formulation often needs to be supplemented by other lubricating additives, which increases the complexity of the formulation.

[0005] In the search for low-foaming solutions, existing technologies have attempted to use natural disproportionated rosin and its derivatives as hydrophobic groups. Disproportionated rosin possesses a rigid hydrogenated phenanthrene backbone, which can effectively disrupt the stability of foam films, making it an ideal low-foaming hydrophobic raw material. For example, directly ethoxylating disproportionated rosin with ethylene oxide yields disproportionated rosin-polyoxyethylene ether ester, which does indeed exhibit low foaming properties. However, the ester bonds in this molecule also face the risk of easy hydrolysis in alkaline working solutions, resulting in insufficient long-term stability and limiting its application in high-end, long-life semi-synthetic liquid products.

[0006] Therefore, developing a multifunctional surfactant that can simultaneously satisfy the requirements of low foaming, good resistance to alkali hydrolysis, and good lubricity has become an urgent technical problem to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this application provides a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, its preparation method, and its application.

[0008] This application uses disproportionated rosin and polyetheramine as raw materials to generate a disproportionated rosin-polyetheramine amide intermediate. The intermediate is then subjected to an ethoxylation reaction with ethylene oxide using its terminal active amino group to obtain a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide. This low-foaming emulsifier is a nonionic surfactant with low foaming, good resistance to alkali hydrolysis and good lubrication properties, and is particularly suitable for semi-synthetic metalworking fluid systems.

[0009] In a first aspect, this application provides a method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, using the following technical solution: A method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide includes the following steps: (1) Disproportionated rosin was reacted with thionyl chloride under the action of catalyst 1, and then polyetheramine was added for further reaction. After alkali washing and separation, disproportionated rosin-polyetheramine amide intermediate was obtained. (2) Using disproportionated rosin-polyetheramine amide intermediate as an initiator, it reacts with ethylene oxide under the action of catalyst 2 to obtain a low-foaming emulsifier.

[0010] By adopting the above technical solution, this application generates a disproportionated rosin-polyetheramine amide intermediate by amidation reaction of disproportionated rosin and polyetheramine. The intermediate is then reacted with ethylene oxide using its terminal active amino group to obtain a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide.

[0011] This application utilizes an innovative molecular structure design to replace traditional ester bonds with chemically more stable amide bonds, thereby significantly improving the resistance to alkaline hydrolysis and giving it superior lubrication properties while retaining the inherent low-foaming advantage of disproportionated rosin.

[0012] This application improves the preparation method to prepare a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide. The low-foaming emulsifier molecule integrates the rigid hydrophobic framework of disproportionated rosin and the polyoxypropylene segment of polyetheramine. Both are classic anti-foaming structural units. Their synergistic effect gives it good low-foaming properties and rapid defoaming ability, which can effectively deal with the dynamic foaming problem in metalworking fluids.

[0013] This application improves the preparation method by using amide bonds as the connecting bonds. The stability of amide bonds under alkaline conditions is much higher than that of ester bonds, which fundamentally solves the technical bottleneck of traditional disproportionated rosin esters and fatty acid ester emulsifiers being prone to hydrolysis and having a short lifespan in semi-synthetic systems. It further improves the alkaline hydrolysis resistance of low-foaming emulsifiers and ensures the long-term stability of the processing fluid system.

[0014] This application improves the preparation method to prepare a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide. The amide group in the low-foaming emulsifier molecule is a strongly polar group that can form a strong chemical adsorption film on the metal surface. At the same time, the flat and rigid structure of the rosin group leads to poorer fluidity and repairability of the foam at the molecular level, and reduced stability of the liquid film, thereby reducing the foam height and increasing the foam collapse rate. The rosin and amide structure provides stronger metal surface adsorption performance than general fatty alcohol polyoxyethylene ethers. Therefore, through the combined effect of the amide structure and the rigid plane of disproportionated rosin, the lubricity of the metalworking fluid is further improved.

[0015] The improvement to the preparation method in this application allows for convenient adjustment of the HLB value of the product by precisely controlling the number of adducts of terminal ethylene oxide, making it suitable for formulating semi-synthetic emulsions with different oil contents. As a result, the prepared low-foaming emulsifier achieves three major functions: foam suppression, good resistance to alkali hydrolysis, and good lubricity, simplifying the formulation structure and improving the system's compatibility and stability.

[0016] Preferably, in step (1), the polyetheramine is a bifunctional group and the molecular weight of the polyetheramine is 230-900.

[0017] More preferably, in step (1), the molecular weight of the polyetheramine is 230.

[0018] More preferably, in step (1), the polyetheramine is polyetheramine D-230.

[0019] Preferably, catalyst 1 in step (1) is N,N-dimethylformamide.

[0020] Preferably, the amount of catalyst 1 added in step (1) is 0.01-0.1% of the mass of disproportionated rosin.

[0021] More preferably, the amount of catalyst 1 added in step (1) is 0.05% of the mass of disproportionated rosin.

[0022] Preferably, in step (1), the reaction temperature is 80-140℃.

[0023] Preferably, in step (1), the molar ratio of disproportionated rosin to thionyl chloride is 1:(0.95-1.05).

[0024] Preferably, in step (1), the molar ratio of disproportionated rosin to polyetheramine is 1:(1-1.05).

[0025] Preferably, in step (1), the alkaline washing and separation steps are as follows: after the reaction is complete, an alkaline solution is added to the product for alkaline washing and separation, and the supernatant is collected, which is the disproportionated rosin-polyetheramine amide intermediate; wherein, the volume ratio of the product to the alkaline solution is 1:(1-5).

[0026] More preferably, the alkaline solution is a sodium hydroxide solution with a mass fraction of 1-5%.

[0027] Preferably, in step (2), the amount of catalyst 2 added is 0.1-0.5% of the total mass of disproportionated rosin-polyetheramine amide intermediate and ethylene oxide.

[0028] More preferably, in step (2), the amount of catalyst 2 added is 0.3% of the total mass of disproportionated rosin-polyetheramine amide intermediate and ethylene oxide.

[0029] Preferably, the catalyst 2 is potassium hydroxide.

[0030] Preferably, the molar ratio of the disproportionated rosin-polyetheramine amide intermediate to ethylene oxide is 1:(5-15).

[0031] In one specific feasible implementation, a method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide includes the following steps: Step 1: Synthesis of disproportionated rosin-polyetheramine: Using disproportionated rosin and thionyl chloride as raw materials, the reaction is carried out at 80-140℃ under the action of catalyst 1 (N,N-dimethylformamide) to obtain its acyl chloride. Then, under vigorous stirring, polyetheramine is added to the mixture to carry out the reaction. After the reaction is completed, according to the volume ratio of product to alkaline solution of 1:(1-5), alkaline solution (1-5% sodium hydroxide solution by mass fraction) is added to the product for alkaline washing and separation. The D230 amide of disproportionated rosin is quenched and released from the product, which is the disproportionated rosin-polyetheramine amide intermediate.

[0032] Step 2: Synthesis of ethoxylated polyethers: The disproportionated rosin-polyetheramine amide intermediate obtained in step one was dehydrated under vacuum for 0.5 hours. Using the disproportionated rosin-polyetheramine amide intermediate as the initiator, catalyst 2 (potassium hydroxide) was added at 105-115℃ and normal pressure (1 atmosphere), and ethylene oxide was introduced to carry out the reaction. The reaction continued until the pressure no longer changed, and a low-foaming emulsifier was obtained.

[0033] Preferably, in step one, the polyetheramine is bifunctional and has a molecular weight of 230-900, preferably 230.

[0034] Preferably, in step one, the degree of amidation is controlled by the acid value. When the polyetheramine used has a molecular weight of 230, the acid value should not exceed 5 mg KOH / g.

[0035] Preferably, in step one, the amount of catalyst 1 added is 0.01-0.1% of the mass of disproportionated rosin.

[0036] Preferably, in step one, the reaction temperature is 80-140℃.

[0037] Preferably, in step one, the molar ratio of the disproportionated rosin to thionyl chloride is 1:(0.95-1.05).

[0038] Preferably, in step one, the molar ratio of disproportionated rosin to polyetheramine is 1:(1-1.05).

[0039] Preferably, in step two, the amount of catalyst 2 added is 0.1-0.5% of the total mass of disproportionated rosin-polyetheramine amide intermediate and ethylene oxide.

[0040] More preferably, in step two, the amount of catalyst 2 added is 0.3% of the total mass of disproportionated rosin-polyetheramine amide intermediate and ethylene oxide.

[0041] Preferably, in step two, the molar ratio of the disproportionated rosin-polyetheramine amide intermediate to ethylene oxide is 1:(5-15).

[0042] Secondly, this application provides a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, using the following technical solution: A low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, wherein the low-foaming emulsifier is prepared by the above method.

[0043] A low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, whose general molecular formula can be characterized as follows: Rosin-CONH-PA-N[(CH2CH2O) n H]2; in: Rosin is a group that represents disproportionated rosin; PA represents the polyetheramine segment, preferably the polyoxypropylene segment; particularly preferred, PA is D230. n is the average addition number of ethylene oxide. Its value can be designed to make the hydrophilic-lipophilic balance of the final product equivalent to that of conventional fatty alcohol polyoxyethylene ethers AEO-3, AEO-5 or AEO-7, in order to meet different emulsification requirements.

[0044] Thirdly, this application provides an application of a low-foaming emulsifier in the preparation of metalworking fluids, employing the following technical solution: Application of a low-foaming emulsifier in the preparation of metalworking fluids.

[0045] In summary, this application includes at least one of the following beneficial technical effects: This application uses disproportionated rosin and polyetheramine as raw materials to generate a disproportionated rosin-polyetheramine amide intermediate. The intermediate is then reacted with ethylene oxide using its terminal active amino group to obtain a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide. The low-foaming emulsifier based on disproportionated rosin-polyetheramine amide prepared in this application is applied to metalworking fluid, so that the prepared metalworking fluid has low foaming, good resistance to alkaline hydrolysis and good lubrication performance. The synthetic route of this application is simple, the conditions are mild, and the product structure is tunable, which has important industrial application value. Detailed Implementation

[0046] The technical solutions of this application are further illustrated by specific embodiments below. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0047] All raw materials involved in this application are commercially available products, among which, Tricarboxylic acid, purchased from BASF L190 PLUS; Sebacic acid, purchased from Shandong Kaisai Biotechnology Co., Ltd.; Triethanolamine, purchased from BASF Yangtze. Dihydroxyethylcyclohexylamine, CAS No.: 4500-29-2; 22# naphthenic base oil, purchased from Karamay Refinery; Fatty alcohol polyoxyethylene ether 3 ether (AEO-3) and fatty alcohol polyoxyethylene ether 7 ether (AEO-7), CAS No.: 68131-39-5.

[0048] Nonylphenol polyoxyethylene ether NP-10 was purchased from Shandong Xinheng Chemical Co., Ltd. Trimethylolpropane oleate, purchased from Shandong Ruijie New Materials Co., Ltd.; BIT-20 fungicide was purchased from Itofuku Biotechnology (Shanghai) Co., Ltd. Defoamer 1247, purchased from Dow Corning; Polyetheramine D-230, CAS No.: 9046-10-0; The present application will be further described in detail below with reference to embodiments and comparative examples.

[0049] Example 1:

[0050] A method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, comprising the following steps: Step 1: Synthesis of disproportionated rosin-polyetheramine: In a four-necked flask equipped with a water separator, condenser, and thermometer, 1 mol (302 g) of disproportionated rosin was added and the temperature was raised to 110 °C. 0.0021 mol (0.151 g) of N,N-dimethylformamide was added as a catalyst. While the disproportionated rosin was softening, 0.95 mol (113 g) of thionyl chloride was slowly added dropwise to carry out the reaction. After the reaction was completed, the temperature was lowered to 80 °C. Then, under vigorous stirring, 1 mol (230 g) of polyetheramine D-230 was slowly added to the mixture to carry out the reaction. After the reaction was completed, 5 times the volume of sodium hydroxide solution (mass concentration of 5%) was added to the product for alkaline washing and material separation. The supernatant was taken to obtain 1 mol (514 g) of disproportionated rosin-polyetheramine amide intermediate. Step 2: Synthesis of ethoxylated polyethers: After dehydrating the disproportionated rosin-polyetheramine amide intermediate obtained above under vacuum for 0.5 hours, it was added to a high-pressure reactor using the disproportionated rosin-polyetheramine amide intermediate as an initiator. 0.039 mol (2.202 g) of potassium hydroxide catalyst was added. The air in the reactor was replaced with nitrogen several times, and then the temperature was raised to 110°C. Under normal pressure (1 atmosphere), 5 mol (220 g) of metered ethylene oxide gas was slowly introduced to carry out the reaction. During the introduction process, the reaction pressure and temperature were controlled (temperature fluctuation ≤ ±5°C, pressure rise rate ≤ 0.05 MPa / min). After the introduction was completed, the mixture was kept at a constant temperature until the pressure no longer dropped. After the reaction was completed, it was cooled to below 80°C, discharged, and neutralized to a weakly acidic state with glacial acetic acid. If necessary, decolorization treatment was performed (e.g., adding 2% activated carbon by weight of the crude product for decolorization treatment) to obtain a low-foaming emulsifier with an HLB value of approximately 8-9.

[0051] Example 2:

[0052] A method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, comprising the following steps: Step 1: Synthesis of disproportionated rosin-polyetheramine: In a four-necked flask equipped with a water separator, condenser, and thermometer, 1 mol (302 g) of disproportionated rosin was added and the temperature was raised to 110 °C. 0.0021 mol (0.151 g) of N,N-dimethylformamide was added as a catalyst. While the disproportionated rosin was softening, 0.95 mol (113 g) of thionyl chloride was slowly added dropwise to carry out the reaction. After the reaction was completed, the temperature was lowered to 80 °C. Then, under vigorous stirring, 1 mol (230 g) of polyetheramine D-230 was slowly added to the mixture to carry out the reaction. After the reaction was completed, 5 times the volume of sodium hydroxide solution (mass concentration of 5%) was added to the product for alkaline washing and material separation. The supernatant was taken to obtain 1 mol (514 g) of disproportionated rosin-polyetheramine amide intermediate. Step 2: Synthesis of ethoxylated polyethers: After dehydrating the disproportionated rosin-polyetheramine amide intermediate obtained above under vacuum for 0.5 hours, it was added to a high-pressure reactor using the disproportionated rosin-polyetheramine amide intermediate as an initiator. 0.051 mol (2.862 g) of potassium hydroxide catalyst was added. The air in the reactor was replaced with nitrogen several times, and then the temperature was raised to 110°C. Under normal pressure (1 atmosphere), 10 mol (440 g) of metered ethylene oxide gas was slowly introduced to carry out the reaction. During the introduction process, the reaction pressure and temperature were controlled (temperature fluctuation ≤ ±5°C, pressure rise rate ≤ 0.05 MPa / min). After the introduction was completed, the mixture was kept at a constant temperature until the pressure no longer dropped. After the reaction was completed, it was cooled to below 80°C, discharged, and neutralized to a weakly acidic state with glacial acetic acid. If necessary, decolorization treatment was performed (e.g., adding 2% activated carbon by weight of the crude product for decolorization treatment) to obtain a low-foaming emulsifier with an HLB value of approximately 11-12.

[0053] Example 3:

[0054] A method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, comprising the following steps: Step 1: Synthesis of disproportionated rosin-polyetheramine: In a four-necked flask equipped with a water separator, condenser, and thermometer, 1 mol (302 g) of disproportionated rosin was added and the temperature was raised to 110 °C. 0.0021 mol (0.151 g) of N,N-dimethylformamide was added as a catalyst. While the disproportionated rosin was softening, 0.95 mol (113 g) of thionyl chloride was slowly added dropwise to carry out the reaction. After the reaction was completed, the temperature was lowered to 80 °C. Then, under vigorous stirring, 1 mol (230 g) of polyetheramine D-230 was slowly added to the mixture to carry out the reaction. After the reaction was completed, 5 times the volume of sodium hydroxide solution (mass concentration of 5%) was added to the product for alkaline washing and material separation. The supernatant was taken to obtain 1 mol (514 g) of disproportionated rosin-polyetheramine amide intermediate. Step 2: Synthesis of ethoxylated polyethers: After dehydrating the disproportionated rosin-polyetheramine amide intermediate obtained above under vacuum for 0.5 hours, it was added to a high-pressure reactor using the disproportionated rosin-polyetheramine amide intermediate as an initiator. 0.063 mol (3.522 g) of potassium hydroxide catalyst was added. The air in the reactor was replaced with nitrogen several times, and then the temperature was raised to 110°C. Under normal pressure (1 atmosphere), 15 mol (660 g) of metered ethylene oxide gas was slowly introduced to carry out the reaction. During the introduction process, the reaction pressure and temperature were controlled (temperature fluctuation ≤ ±5°C, pressure rise rate ≤ 0.05 MPa / min). After the introduction was completed, the mixture was kept at a constant temperature until the pressure no longer dropped. After the reaction was completed, it was cooled to below 80°C, discharged, and neutralized to a weakly acidic state with glacial acetic acid. If necessary, decolorization treatment was performed (e.g., adding 2% activated carbon by weight of the crude product for decolorization treatment) to obtain a low-foaming emulsifier with an HLB value of approximately 14-15.

[0055] Application performance testing:

[0056] The low-foaming emulsifier sample prepared in the above embodiments was mixed with commercially available AEO3, AEO7, and NP-10 samples and added to the metalworking fluid in the following proportions to prepare the metalworking fluid, as shown in Table 1.

[0057] Table 1. Composition of Metalworking Fluid Raw Materials

[0058] The thermal storage stability, circulating foam height, defoaming speed, and tapping torque of the metalworking fluid prepared by the above formula were tested using the following methods: 1. Thermal storage stability: Place the test sample in a 55℃ constant temperature chamber and let it stand for 30 days. Observe whether there is any precipitation, sedimentation, or turbidity. The result is qualified if the appearance is clear, there is no precipitation, and there is no layering.

[0059] 2. Foam testing method: Testing instrument: Guangdong Platinum Metalworking Fluid Stability Tester, model: BSV-11; 2.1 Circulating foam height: The sample was diluted with deionized water to obtain a 5% volume concentration diluted solution. The solution was circulated for 8 hours, with an initial liquid level of 800 ml. The foam height was recorded.

[0060] Judgment: The higher the foam height, the worse its foam performance.

[0061] 2.2 Defoaming speed: Dilute the test sample with deionized water to obtain a 5% volume concentration diluted solution. Circulate for 8 hours, with an initial liquid level of 800 ml. Stop the circulation and start timing until the liquid level leaks out to the center of the liquid surface. Record the defoaming time.

[0062] Judgment: The shorter the defoaming time, the better its foaming performance.

[0063] 3. Tapping torque value detection: Material: 7075 aluminum alloy, cutting tool: M4F, hole depth 10mm, cutting tool speed: 1500rpm, machine: German MicrotapTTT system tapping torque machine.

[0064] Result determination: The lower the tapping torque value, the better the lubrication.

[0065] Table 2 Application Test Results

[0066] As shown in Tables 1 and 2, the low-foaming emulsifiers prepared in Examples 1-3 of this application, when added to metalworking fluids, produce metalworking fluids with low foaming, good resistance to alkali hydrolysis, and good lubrication properties, making them suitable for the production of metalworking fluids. By precisely controlling the number of ethylene oxide additions at the end, this application can easily adjust the HLB value of the product, making it suitable for formulating semi-synthetic emulsions with different oil contents. Thus, the prepared low-foaming emulsifier achieves three major functions: low foaming, good resistance to alkali hydrolysis, and good lubrication, simplifying the formulation structure and improving the system compatibility and stability.

[0067] As shown in Tables 1 and 2, the low-foaming emulsifiers prepared in Examples 1-3 of this application, when added to the metalworking fluid, produce a metalworking fluid with low foaming and good defoaming properties. This indicates that the low-foaming emulsifiers prepared in this application can provide stronger defoaming functions. This is mainly because the low-foaming emulsifier molecules prepared in this application simultaneously integrate the rigid hydrophobic framework of disproportionated rosin and the polyoxypropylene segment of polyetheramine. Both are classic foam-suppressing structural units, and their synergistic effect gives them good low-foaming properties and rapid defoaming ability, which can effectively address the dynamic foaming problem in metalworking fluids.

[0068] As shown in Tables 1 and 2, the low-foaming emulsifiers prepared in Examples 1-3 of this application, when added to the metalworking fluid, resulted in a metalworking fluid with good thermal stability. This indicates that the low-foaming emulsifiers prepared in this application can provide stronger resistance to alkaline hydrolysis. This is mainly because amide bonds are used as the connecting bonds in this application. The stability of amide bonds under alkaline conditions is much higher than that of ester bonds, thereby fundamentally solving the technical bottleneck of easy hydrolysis and short lifespan of traditional disproportionated rosin esters and fatty acid ester emulsifiers in semi-synthetic systems. This further improves the alkaline hydrolysis resistance of the low-foaming emulsifier and ensures the long-term stability of the metalworking fluid system.

[0069] As shown in Tables 1 and 2, the low-foaming emulsifiers prepared in Examples 1-3 of this application, when added to the metalworking fluid, resulted in a metalworking fluid with good lubrication performance. This indicates that the low-foaming emulsifiers prepared in this application can provide stronger auxiliary lubrication function. This is mainly because the amide group in the low-foaming emulsifier molecule is a strongly polar group, which can form a strong chemical adsorption film on the metal surface. At the same time, the rosin group has a flat and rigid structure, which leads to poorer fluidity and repairability of the foam at the molecular level and reduced stability of the liquid film, thereby reducing the height of the foam and increasing the foam collapse rate. The rosin and amide structure provide stronger metal surface adsorption performance than general fatty alcohol polyoxyethylene ethers. Therefore, through the combined action of the amide structure and the rigid plane of disproportionated rosin, the lubricity of the metalworking fluid is further improved.

[0070] The technical features of the above-described embodiments and examples can be combined in any suitable manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Furthermore, it should be understood that after reading the above teachings of this application, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the scope of protection of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide, characterized in that: Includes the following steps: (1) Disproportionated rosin was reacted with thionyl chloride under the action of catalyst 1, and then polyetheramine was added for further reaction. After alkaline washing and separation, disproportionated rosin-polyetheramine amide intermediate was obtained. (2) Using disproportionated rosin-polyetheramine amide intermediate as an initiator, it reacts with ethylene oxide under the action of catalyst 2 to obtain a low-foaming emulsifier.

2. The method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide according to claim 1, characterized in that: In step (1), the polyetheramine is a bifunctional group and the molecular weight of the polyetheramine is 230-900.

3. The method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide according to claim 1, characterized in that: In step (1), catalyst 1 is N,N-dimethylformamide.

4. The method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide according to claim 1, characterized in that: In step (1), the reaction temperature is 80-140℃.

5. The method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide according to claim 1, characterized in that: In step (1), the alkaline washing step is as follows: after the reaction is complete, an alkaline solution is added to the product for alkaline washing, wherein the volume ratio of the product to the alkaline solution is 1:(1-5).

6. The method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide according to claim 1, characterized in that: In step (1), the amount of catalyst 1 added is 0.01-0.1% of the mass of disproportionated rosin; In step (1), the molar ratio of disproportionated rosin to thionyl chloride is 1:(0.95-1.05). In step (1), the molar ratio of disproportionated rosin to polyetheramine is 1:(1-1.05).

7. The method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide according to claim 1, characterized in that: In step (2), catalyst 2 is potassium hydroxide.

8. The method for preparing a low-foaming emulsifier based on disproportionated rosin-polyetheramine amide according to claim 1, characterized in that: In step (2), the amount of catalyst 2 added is 0.1-0.5% of the total mass of disproportionated rosin-polyetheramine amide intermediate and ethylene oxide; In step (2), the molar ratio of disproportionated rosin-polyetheramine amide intermediate to ethylene oxide is 1:(5-15).

9. A low-foaming emulsifier, characterized in that: The low-foaming emulsifier is prepared by the method described in any one of claims 1-8.

10. The use of the low-foaming emulsifier prepared by the method of any one of claims 1-8, or the low-foaming emulsifier of claim 9, in the preparation of metalworking fluids.

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