Anti-foaming agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of lubricating oil additives, and particularly relates to an anti-foaming agent and a preparation method and application thereof. The anti-foaming agent provided by the invention is a copolymer of a monomer 1 and a monomer 2, the monomer 1 comprises 2-ethylhexyl acrylate, and the monomer 2 comprises one or two of ethyl acrylate, styrene and butyl acrylate. The anti-foaming agent provided by the invention has good thermal stability and can adapt to long-term use in a higher-temperature environment; meanwhile, the anti-foaming agent provided by the invention has good compatibility with mineral oil, synthetic oil and other oil substances, and can be uniformly dispersed in lubricating oil. The anti-foaming agent provided by the invention has an excellent anti-foaming effect when being used in high-viscosity lubricating oil.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lubricating oil additives, and particularly relates to an antifoam agent and a preparation method and application thereof. BACKGROUND

[0002] Foam is easily generated in lubricating oil under high-speed shearing or high-temperature working conditions. In a lubricating oil system, the generation and accumulation of foam can significantly affect the heat dissipation performance, lubricating film formation and pumping efficiency of the lubricating oil, thereby leading to lubrication failure. Even the generation of foam can cause cavitation and equipment damage. Therefore, the antifoam agent has been widely used as a functional additive in industrial lubricating formulations. At present, the main method for improving the foam performance of lubricating oil is to add an antifoam agent into the lubricating oil.

[0003] The commonly used antifoam agents in the industry mainly include organic silicon antifoam agents (such as polydimethylsiloxane, PDMS, etc.) and polyether antifoam agents (such as polypropylene glycol, polyether modified silicone oil, etc.). Although the existing antifoam agents can provide certain foam inhibition and defoaming effects in normal temperature and medium-low viscosity base oils, the foam inhibition effect is limited under more severe application conditions (high temperature or high viscosity lubricating oil). The organic silicon antifoam agent has extremely low surface tension and can quickly break the foam after foaming, but it is prone to thermal degradation or migration under high-temperature environment, resulting in unstable antifoam effect. At the same time, the structural difference between the organic silicon antifoam agent and the lubricating oil base oil is large, and the dispersibility is poor in high viscosity base oil (such as PAO-500N and above), which is easy to aggregate, settle or cause interface stratification. The polyether antifoam agent has poor oil solubility in non-polar lubricating oil due to the large number of hydrophilic ether bonds in the molecule, which often shows initial effectiveness and long-term failure, and easily causes compatibility problems in the formulation system, thereby limiting its application in high load, high shear and high temperature scenes.

[0004] The existing antifoam agents are difficult to simultaneously meet the requirements of dispersion stability in high viscosity base oil system and thermal stability under high temperature working conditions, which easily leads to performance fluctuation or failure of the antifoam agent. SUMMARY

[0005] Therefore, the application provides an antifoam agent and a preparation method and application thereof. The antifoam agent has good oil compatibility and can efficiently resist foam in high viscosity lubricating oil under high temperature conditions.

[0006] In order to solve the above technical problems, the application provides an antifoam agent, which is a copolymer of monomer 1 and monomer 2.

[0007] The monomer 1 includes isooctyl acrylate, and the monomer 2 includes one or two of ethyl acrylate, styrene and butyl acrylate.

[0008] Preferably, the molar percentage content of the monomer 1 in the copolymer is 60-80%.

[0009] Preferably, the monomer 2 is a mixture of ethyl acrylate and styrene, a mixture of ethyl acrylate and butyl acrylate or ethyl acrylate.

[0010] Preferably, when the monomer 2 is a mixture of ethyl acrylate and styrene, the molar percentage of styrene in the monomer 2 is greater than 0 and less than or equal to 50%.

[0011] When the monomer 2 is a mixture of ethyl acrylate and butyl acrylate, the molar percentage of butyl acrylate in the monomer 2 is greater than 0 and less than or equal to 50%.

[0012] The present application also provides a preparation method of the anti-foaming agent described in the above technical solution, comprising the following steps:

[0013] After mixing the monomer 1, the monomer 2, the organic solvent and the initiator, a polymerization reaction is carried out to obtain the anti-foaming agent.

[0014] Preferably, the mixing comprises the following steps:

[0015] The monomer 1 and the monomer 2 are first mixed to obtain a first mixed solution;

[0016] The first mixed solution, the organic solvent and the initiator are second mixed;

[0017] The organic solvent comprises ethyl acetate.

[0018] The initiator comprises azobisisobutyronitrile or dibenzoyl peroxide, and the molar ratio of the total molar amount of the monomer 1 and the monomer 2 to the initiator is 100:0.4-1.0.

[0019] Preferably, the temperature of the polymerization reaction is 70-80℃, and the time is 6-8h.

[0020] Preferably, after the polymerization reaction, the following steps are included: after mixing the system after the polymerization reaction and methanol, the system is sequentially subjected to standing and separation; the viscous liquid obtained by the separation is dried to obtain the anti-foaming agent.

[0021] The present application also provides the application of the anti-foaming agent described in the above technical solution or the anti-foaming agent prepared by the preparation method described in the above technical solution in lubricating oil.

[0022] Preferably, the 40℃ kinematic viscosity of the lubricating oil is 12-180mm 2 / s;

[0023] The addition amount of the anti-foaming agent in the lubricating oil is 0.005-0.3wt%.

[0024] The present application provides an antifoaming agent, which is a copolymer of monomer 1 and monomer 2; the monomer 1 comprises isooctyl acrylate, and the monomer 2 comprises one or two of ethyl acrylate, styrene and butyl acrylate. The antifoaming agent provided by the present application has good thermal stability and can be used for a long time in a higher temperature environment; meanwhile, the antifoaming agent provided by the present application has good compatibility with oil substances such as mineral oil and synthetic oil, and can be uniformly dispersed in lubricating oil. The antifoaming agent provided by the present application has excellent antifoaming effect when used in high-viscosity lubricating oil. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 1H-NMR spectrum of the antifoaming agent prepared for Example 1;

[0026] Figure 2 13C NMR spectrum of the antifoaming agent prepared for Example 1;

[0027] Figure 3 Thermogravimetric curve of the antifoaming agent prepared for Example 1;

[0028] Figure 4 Actual photos of 500N base oil and 500N base oil added with the antifoaming agent of Example 1 after bubbling for 5 min. DETAILED DESCRIPTION

[0029] The present application provides an antifoaming agent, which is a copolymer of monomer 1 and monomer 2;

[0030] In the present application, the monomer 1 comprises isooctyl acrylate.

[0031] In the present application, the monomer 2 comprises one or two of ethyl acrylate, styrene and butyl acrylate, which can be specifically a mixture of ethyl acrylate and styrene, a mixture of ethyl acrylate and butyl acrylate or ethyl acrylate. As a specific embodiment of the present application, when the monomer 2 is a mixture of ethyl acrylate and styrene, the molar percentage content of styrene in the monomer 2 can be greater than 0 and less than or equal to 50%, which can be specifically 5%, 10%, 15%, 20%, 30%, 40% or 50%; when the monomer 2 is a mixture of ethyl acrylate and butyl acrylate, the molar percentage content of butyl acrylate in the monomer 2 can be greater than 0 and less than or equal to 50%, which can be specifically 5%, 10%, 15%, 20%, 30%, 40% or 50%.

[0032] As a specific embodiment of the present application, the mole percentage of monomer 1 in the copolymer can be 60-80%, and can be specifically 60%, 65%, 68%, 70%, 73%, 75%, or 80%. As a specific embodiment of the present application, the number average molecular weight of the copolymer can be 40,000-80,000.

[0033] The polyisooctyl acrylate polymer in the copolymer of the present application has a full-carbon skeleton and a long-chain branched hydrophobic structure, has a molecular configuration highly matched with a lubricating oil system, can realize thermodynamic dissolution at a molecular scale in a nonpolar oil phase, and exhibits more excellent oil compatibility and dispersion stability compared with traditional silicon-based (such as PDMS) or polyether-based antifoams (such as PPG and PEG). The present application can effectively improve the rigidity and glass transition temperature of the polymer chain segment by introducing a short-chain monomer (monomer 2) into the polymer main chain, thereby endowing the material with stronger thermal stability and interfacial durability, so that it can still maintain stable antifoam performance and interfacial adsorption behavior under harsh working conditions such as high temperature, high shear, and high viscosity. The antifoam provided by the present application has a synergistic improvement in oil phase compatibility and thermal physical stability.

[0034] The present application also provides a preparation method of the antifoam described in the above technical solution, comprising the following steps: mixing monomer 1, monomer 2, an organic solvent, and an initiator, and then performing a polymerization reaction to obtain the antifoam.

[0035] In the present application, all materials are conventional commercially available products if not otherwise specified.

[0036] As a specific embodiment of the present application, the mixing can comprise the following steps:

[0037] Monomer 1 and monomer 2 are first mixed to obtain a first mixed solution;

[0038] The first mixed solution, an organic solvent, and an initiator are second mixed.

[0039] The present application first mixes monomer 1 and monomer 2 to obtain a first mixed solution. The present application has no special requirements for the first mixing, as long as the materials can be uniformly mixed. As a specific embodiment of the present application, the first mixing can further comprise: performing water removal treatment on the first mixed system. The present application has no special requirements for the water removal treatment mode, and a conventional mode in the art can be used. The present application can prevent side reactions from occurring through water removal treatment.

[0040] After obtaining the first mixture, the present application second mixes the first mixture, an organic solvent and an initiator. As one specific embodiment of the present application, the initiator can include azobisisobutyronitrile or dibenzoyl peroxide, and the molar ratio of the total moles of monomer 1 and monomer 2 to the moles of initiator can be 100:0.4-1.0, and can specifically be 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9 or 100:1.0. The present application does not have special requirements for the second mixing, as long as it can be uniformly mixed.

[0041] As one specific embodiment of the present application, the temperature of the polymerization reaction can be 70-80℃, and can specifically be 70℃, 73℃, 75℃, 78℃ or 80℃; the time of the polymerization reaction can be 6-8h, and can specifically be 6h, 6.5h, 7h, 7.5h or 8h. As one specific embodiment of the present application, the polymerization reaction can be carried out under a protective atmosphere, and the protective atmosphere can include nitrogen or argon.

[0042] As one specific embodiment of the present application, the polymerization reaction can further include: after mixing the polymerization reaction system and methanol, sequentially carrying out standing and separation; drying the viscous liquid obtained by the separation to obtain the antifoaming agent. As one specific embodiment of the present application, the volume ratio of the polymerization reaction system to methanol can be 1:3-5, and can specifically be 1:3, 1:3.5, 1:4, 1:4.5 or 1:5. The present application does not have special limitations on the time of the standing, as long as it can be stratified. As one specific embodiment of the present application, the separation can include filtering or pouring to remove supernatant; the present application does not have special limitations on the filtering, and a conventional manner in the art can be used. As one specific embodiment of the present application, the temperature of the drying can be 40-60℃, and can specifically be 40℃, 45℃, 50℃, 55℃ or 60℃; the time of the drying can be 4-12h, and can specifically be 4h, 5h, 6h, 8h, 10h or 12h; the drying can be carried out under vacuum conditions, and the present application does not have special limitations on the vacuum degree of the vacuum conditions, as long as it is vacuum. The present application can remove the unreacted monomers, initiators and solvent residues in the system by mixing with methanol (the antifoaming agent is insoluble in methanol, and the unreacted monomers, initiators and solvent are miscible with methanol); the present application can further remove the residual solvent in the viscous liquid by drying. In the present application, the antifoaming agent is a viscous liquid.

[0043] The present application also provides the use of the antifoaming agent in the above technical solution or the antifoaming agent prepared by the preparation method in the above technical solution in lubricating oil. As one specific embodiment of the present application, the 40℃ kinematic viscosity of the lubricating oil can be 12-180mm 2 / s, and can also be 30 to 150 mm 2 / s; the base oil of the lubricating oil may include 150N, 400N, 500N, 650N or 750N, PAO4, PAO10, or trimellitate; the amount of the antifoaming agent added to the lubricating oil may be 0.005~0.3wt%, or 0.01~0.25wt%.

[0044] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] 0.43 mol of isooctyl acrylate and 0.2 mol of monomer 2 (ethyl acrylate) were first mixed and then subjected to water removal treatment (mixed with anhydrous sodium sulfate for 30 minutes and filtered) to obtain a first mixed solution;

[0047] 0.003 mol of azobisisobutyronitrile (initiator) and 100 mL of ethyl acetate (solvent) were added to the first mixed liquid, mixed evenly, and then a polymerization reaction was carried out at 70°C under a nitrogen atmosphere for 8 hours; the system after the polymerization reaction was mixed with methanol (the volume ratio of the system after the polymerization reaction to methanol was 1:3), allowed to stand for stratification, and then filtered. The viscous liquid obtained by filtration was dried at 45°C for 4 hours to obtain an anti-foaming agent.

[0048] Example 2

[0049] An antifoaming agent was prepared according to the method of Example 1, except that monomer 2 consisted of 0.1 mol of ethyl acrylate and 0.1 mol of styrene.

[0050] Example 3

[0051] An antifoaming agent was prepared according to the method of Example 1, except that monomer 2 was 0.1 mol of ethyl acrylate and 0.1 mol of butyl acrylate.

[0052] Comparative Example 1

[0053] A commercially available poly(isooctyl acrylate) with a molecular weight of about 60K was used as a comparative example.

[0054] Comparative Example 2

[0055] An antifoaming agent was prepared according to the method of Example 1, except that monomer 2 was lauryl acrylate.

[0056] The antifoaming agent prepared in Example 1 was 1 H-NMR and 13CNMR tests revealed 1 H-NMR spectrum Figure 1The obtained 13C NMR spectrum is shown in Figure 1. Figure 2 The obtained 13C NMR spectrum is shown in Figure 1. Figure 1 The following key characteristic peaks can be observed in the 13C NMR spectrum: a broad multiplet at δ ≈ 3.8-4.2 ppm, which is characteristic of the methylene group (-OCH2-) adjacent to the ester group, confirming the presence of ester linkage in the molecular structure; a broad peak at δ ≈ 1.6-2.2 ppm, which is attributed to the methylene (-CH2-) units in the polymer backbone, while the broad peak at 2.2-2.6 ppm is from the methine (-CH-) in the backbone, which is consistent with the backbone of the acrylic ester polymer (the high peak at 2.04 ppm is from the removed solvent ethyl acetate); the terminal methyl group -CH3 (δ ≈ 0.7-1.0 ppm), methylene group -CH2- (1.2-1.5 ppm), and methine group -CH- (1.5-1.7 ppm) in the isooctyl branch are clearly visible, while the broad triplet of the ethyl methyl group (-CH3) from the ethyl acrylate branch is located at 1.1-1.3 ppm. Figure 2 As can be seen from the 13C NMR spectrum of

[0057] High temperature stability: The anti-foaming agent prepared in Example 1 was subjected to thermogravimetric analysis (TGA); the test was carried out in air atmosphere at a heating rate of 10°C / min and an inlet air rate of 100 mL / min, and the results are shown in Figure 3. Figure 3 The results show that the mass of the sample remains stable at 90°C, indicating that it can meet the use requirements in the typical working temperature range of the lubricating system. The thermogravimetric curve further shows that the polymer has no significant mass loss before 200°C, indicating that the material has good thermal stability and can be used for long-term use in higher temperature environments. As the temperature rises to 350°C, the mass loss of the sample reaches about 50%, indicating that this temperature is the starting point of the main pyrolysis stage. Overall, the decomposition temperature of this polymer is higher than the upper limit of the conventional lubricating system (100°C), and it has good thermal stability and structural integrity, making it suitable as a structural platform for lubricating oil anti-foaming agents or surface functional additives under high temperature working conditions.

[0058] Compatibility: The anti-foaming agent prepared in Example 1 and the anti-foaming agent of Comparative Example 1 were added into 150N, 500N, 750N, PAO4, PAO10 base oil respectively with an addition amount of 0.3wt%, the anti-foaming agent of Example 1 can be completely dissolved in the oil sample, and still presents a uniform solution after standing at room temperature for 24h; it is indicated that the anti-foaming agent has good compatibility with the base oil.

[0059] Anti-foaming performance: According to the national standard GB / T 12579-2002, the anti-foaming agents of Examples 1-3 and Comparative Examples 1-2 were added into 500N (viscosity about 100mm 2 / s) base oil with an addition amount of 0.3wt%, and the foam tendency and foam stability were detected at different temperatures, and the results are shown in Table 1.

[0060] Table 1 Anti-foaming performance of the anti-foaming agents of Examples 1-3 and Comparative Examples 1-2

[0061]

[0062]

[0063] According to the method of GB / T 12579-2002, the 500N base oil and the 500N base oil added with the anti-foaming agent of Example 1 (addition amount of 0.3wt%) were respectively bubbled for 5min at room temperature (25℃), the foam volume in the 500N base oil was 200ml, while the foam volume in the 500N base oil added with the anti-foaming agent of Example 1 was 0; the actual picture is shown in Figure 4 , the left side is the result picture of the 500N base oil, and the right side is the result picture of the 500N base oil added with the anti-foaming agent.

[0064] From the results of Table 1 and Figure 4 , it can be seen that the anti-foaming agent provided by the present application can reduce the foam volume by more than 90% when added into medium-high viscosity base oil, and also achieve good anti-foaming effect under high temperature conditions.

[0065] The anti-foaming agent provided by the present application has the following advantages: excellent system compatibility: good compatibility with organic systems such as lubricating oil, and not easy to cause turbidity or precipitation of oil products; high shear stability: not easy to fail under strong stirring or high-speed flow conditions, suitable for mechanical lubrication system; good thermal stability: suitable for high temperature environment, and the defoaming effect is durable.

[0066] Although the above examples have made a detailed description of the present application, it is only a part of the embodiments of the present application, but not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. An antifoaming agent, characterized in that is a copolymer of monomer 1 and monomer 2; The monomer 1 includes isooctyl acrylate, and the monomer 2 includes one or two of ethyl acrylate, styrene, and butyl acrylate.

2. The antifoaming agent according to claim 1, characterized in that The molar percentage of monomer 1 in the copolymer is 60-80%.

3. The antifoaming agent according to claim 1, characterized in that The monomer 2 is a mixture of ethyl acrylate and styrene, a mixture of ethyl acrylate and butyl acrylate, or ethyl acrylate.

4. The antifoaming agent according to claim 3, characterized in that When the monomer 2 is a mixture of ethyl acrylate and styrene, the molar percentage of styrene in the monomer 2 is greater than 0 and less than or equal to 50%; When the monomer 2 is a mixture of ethyl acrylate and butyl acrylate, the molar percentage of butyl acrylate in the monomer 2 is greater than 0 and less than or equal to 50%.

5. The method for preparing the antifoaming agent according to any one of claims 1 to 4, characterized in that: The following steps are involved: The monomer 1, the monomer 2, the organic solvent and the initiator are mixed and then subjected to polymerization reaction to obtain the antifoaming agent.

6. The preparation method according to claim 5, characterized in that: The mixing comprises the following steps: Mixing monomer 1 and monomer 2 to obtain a first mixed solution; mixing the first mixed solution, the organic solvent and the initiator for a second time; The organic solvent includes ethyl acetate; The initiator includes azobisisobutyronitrile or dibenzoyl peroxide, and the molar ratio of the total molar amount of the monomer 1 and the monomer 2 to the initiator is 100:0.4-1.

0.

7. The preparation method according to claim 5 or 6, characterized in that: The polymerization reaction temperature is 70-80° C. and the reaction time is 6-8 hours.

8. The preparation method according to claim 7, characterized in that: The method comprises the following steps after the polymerization reaction: mixing the system after the polymerization reaction with methanol, and then sequentially allowing the mixture to stand and separate; and drying the viscous liquid obtained by the separation to obtain the antifoaming agent.

9. Use of the antifoaming agent according to any one of claims 1 to 4 or the antifoaming agent prepared by the preparation method according to any one of claims 5 to 8 in lubricating oil.

10. The use according to claim 9, characterized in that: The kinematic viscosity of the lubricating oil at 40°C is 12 to 180 mm 2 / s; The antifoaming agent is added to the lubricating oil in an amount of 0.005 to 0.3 wt%.

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