Self-lubricating microcapsule as well as preparation method and application thereof

Abstract

The invention relates to the technical field of lubricants, in particular to a self-lubricating microcapsule as well as a preparation method and application thereof. Wherein the self-lubricating microcapsule is prepared from the following preparation raw materials in parts by mass: 38 to 42 parts of lubricating oil composition, 8 to 12 parts of monomer mixture, 3 to 4 parts of surfactant, 0.5 to 1 part of initiator, 0.05 to 0.15 part of cross-linking agent and 180 to 220 parts of deionized water; the monomer mixture comprises ethyl methacrylate, styrene and butyl acrylate. According to the self-lubricating microcapsule disclosed by the invention, the capsule wall is formed by a plurality of monomers, so that the self-lubricating microcapsule has good mechanical performance, and in addition, the microcapsule is endowed with good lubricating performance by further matching with a lubricating oil composition for use.

Description

Technical Field

[0001] The invention relates to the technical field of lubricants, and in particular to a self-lubricating microcapsule, a preparation method and application thereof. Background Art

[0002] Microcapsule self-lubricating polymer material is a new type of self-lubricating material, which is widely used in mechanical parts in the fields of aerospace, oil field and chemical industry.

[0003] Microcapsules have a "core-shell" structure. The capsule core is filled with lubricants, and the capsule wall is generally made of materials with higher melting points. The capsule wall of the microcapsule is mainly made of polydopamine (PDA), melamine urea-formaldehyde resin (MUF), polymethyl methacrylate (PMMA), graphite, SiO2, CaCO3 and other materials. Among them, the capsule wall made of inorganic materials usually has a relatively complex synthesis process, resulting in low quality of the microcapsules. The capsule wall made of organic materials has the problem of poor density and brittleness, which will affect the lubrication performance and service life of the material.

[0004] It can be seen that the existing technology still needs to be improved and enhanced. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a self-lubricating microcapsule, a preparation method and application thereof, aiming to further improve the lubricating performance of the microcapsule.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention provides a self-lubricating microcapsule, wherein the raw materials for its preparation include, by weight: 38 to 42 parts of a lubricating oil composition, 8 to 12 parts of a monomer mixture, 3 to 4 parts of a surfactant, 0.5 to 1 part of an initiator, 0.05 to 0.15 parts of a crosslinking agent and 180 to 220 parts of deionized water; the monomer mixture includes ethyl methacrylate, styrene and butyl acrylate.

[0007] The self-lubricating microcapsule, wherein the lubricating oil composition comprises perfluoropolyether and ionic liquid.

[0008] The self-lubricating microcapsule, wherein the ionic liquid includes at least one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-octylimidazole tetrafluoroborate, 1-allyl-3-methylimidazolium hexafluorophosphate, and trihexyl (tetradecyl) phosphine diisooctyl phosphate.

[0009] The self-lubricating microcapsule, wherein the mass ratio of the perfluoropolyether to the ionic liquid is (1.2-1.5):1.

[0010] The self-lubricating microcapsules, wherein the mass ratio of ethyl methacrylate, styrene and butyl acrylate is (4-5):(2-1):1.

[0011] The self-lubricating microcapsules, wherein the surfactant comprises a nonionic surfactant and a reactive surfactant.

[0012] The self-lubricating microcapsules, wherein the nonionic surfactant includes at least one of sorbitan monolaurate, sorbitan monopalmitate, and sorbitan monostearate; the reactive surfactant includes at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and dodecyltrimethylammonium chloride.

[0013] The self-lubricating microcapsule, wherein the crosslinking agent includes at least one of allyl methacrylate, trimethylolpropane triacrylate, acetoacetoxyethyl methacrylate, ethylene glycol diacrylate, and 1,4-butanediol diacrylate.

[0014] The second aspect of the present invention provides a method for preparing microcapsules, which is used to prepare the self-lubricating microcapsules as described above, comprising the following steps: Mix deionized water and surfactant in a water bath, then add the lubricating oil composition while stirring, and stir for 20 to 30 minutes; Adding a monomer mixture, a crosslinking agent and an initiator in sequence, reacting at 75 to 80° C. for 8 to 10 hours to obtain a reaction solution; The reaction liquid is filtered, washed and dried to obtain the self-lubricating microcapsules.

[0015] The third aspect of the present invention provides the use of the self-lubricating microcapsules as described above as lubricants in polymer materials.

[0016] Beneficial effects: The first aspect of the present invention provides a self-lubricating microcapsule, which uses ethyl methacrylate, styrene, butyl acrylate and a cross-linking monomer to form a high-density and high-strength polymer capsule wall, and uses a lubricating oil composition as the capsule core, thereby comprehensively improving the lubrication performance of the microcapsule.

[0017] The second aspect of the present invention provides a method for preparing microcapsules, which is used to prepare the self-lubricating microcapsules described above. The method has simple process steps, high controllability, and the quality of the prepared microcapsules is stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a transmission electron micrograph of the self-lubricating microcapsules prepared in Example 1.

[0019] Figure 2This is the C element distribution diagram of the self-lubricating microcapsules prepared in Example 1.

[0020] Figure 3 This is the O element distribution diagram of the self-lubricating microcapsules prepared in Example 1.

[0021] Figure 4 This is the F element distribution diagram of the self-lubricating microcapsules prepared in Example 1.

[0022] Figure 5 This is a digital photo of the self-lubricating microcapsules prepared in Example 1.

[0023] Figure 6 This is a scanning electron microscope image of the self-lubricating microcapsules prepared in Example 1.

[0024] Figure 7 This is the particle size distribution diagram of the self-lubricating microcapsules prepared in Example 1.

[0025] Figure 8 Graph showing the coefficient of friction of the embodiment.

[0026] Fig. 9 It is the friction coefficient diagram of the comparative example and the blank group. DETAILED DESCRIPTION

[0027] The present invention provides a self-lubricating microcapsule, a preparation method and application thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] The first aspect of the present invention provides a self-lubricating microcapsule, wherein the raw materials for its preparation include, by weight: 38 to 42 parts of a lubricating oil composition, 8 to 12 parts of a monomer mixture, 3 to 4 parts of a surfactant, 0.5 to 1 part of an initiator, 0.05 to 0.15 parts of a crosslinking agent and 180 to 220 parts of deionized water; the monomer mixture includes ethyl methacrylate, styrene and butyl acrylate.

[0029] Among the above components, the lubricating oil composition is used as the capsule core. When encountering high friction resistance, the capsule wall of the microcapsule will be destroyed, thereby releasing the lubricating oil composition, thereby exerting a highly efficient lubricating effect. Ethyl methacrylate, styrene, butyl acrylate and crosslinking agent participate in the formation of the capsule wall. The capsule wall has a certain hardness and has a certain lubricating effect, thereby preventing the lubricating oil composition with a highly efficient lubricating effect inside from being released prematurely.

[0030] Preferably, the lubricating oil composition comprises perfluoropolyether (PFPE) and ionic liquid. By compounding perfluoropolyether and ionic liquid, the lubricating effect of the self-lubricating microcapsule can be effectively improved. The molecular weight of the perfluoropolyether is 3000-4000.

[0031] Preferably, the ionic liquid includes at least one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-octylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium hexafluorophosphate, and trihexyl (tetradecyl)phosphine diisooctyl phosphate.

[0032] Preferably, the mass ratio of the perfluoropolyether to the ionic liquid is (1.2-1.5): 1. At this ratio, the lubricating performance of the lubricating oil composition is better.

[0033] Preferably, the mass ratio of ethyl methacrylate, styrene and butyl acrylate is (4-5): (2-1): 1. Under this ratio, the capsule wall has sufficient hardness and certain toughness. When used with a crosslinking agent, a denser capsule wall can be formed, so that the application effect of the microcapsule is better.

[0034] Preferably, the surfactant includes a nonionic surfactant and a reactive surfactant. The use effect can be improved by compounding the nonionic surfactant and the reactive surfactant.

[0035] Preferably, the nonionic surfactant includes at least one of sorbitan monolaurate, sorbitan monopalmitate, and sorbitan monostearate; and the reactive surfactant includes at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and dodecyltrimethylammonium chloride.

[0036] Preferably, the crosslinking agent includes at least one of allyl methacrylate, trimethylolpropane triacrylate, ethyl acetoacetate methacrylate, ethylene glycol diacrylate, and 1,4-butanediol diacrylate.

[0037] The second aspect of the present invention provides a method for preparing microcapsules, which is used to prepare the self-lubricating microcapsules as described above, comprising the following steps: Mix deionized water and surfactant in a water bath, then add the lubricating oil composition while stirring, and stir for 20 to 30 minutes; Adding a monomer mixture, a crosslinking agent and an initiator in sequence, reacting at 75 to 80° C. for 8 to 10 hours to obtain a reaction solution; The reaction liquid is filtered, washed and dried to obtain the self-lubricating microcapsules.

[0038] The third aspect of the present invention provides the use of the self-lubricating microcapsules as described above as lubricants in polymer materials. Specifically, the self-lubricating microcapsules of the present invention can be applied to polymer materials such as organic polymer coatings and microcapsule composite liners.

[0039] The present invention is further described below with reference to specific examples and comparative examples.

[0040] Example 1 A self-lubricating microcapsule, the preparation method thereof comprises the following steps, calculated by weight: 200 parts of deionized water and 3 parts of surfactant were mixed under heating in a water bath, and then 40 parts of lubricating oil composition were added while stirring, and stirred for 30 minutes; Add 10 parts of the monomer mixture, 0.1 parts of the crosslinking agent and 0.5 parts of the initiator, and react at 75-80° C. for 8 hours to obtain a reaction solution; The reaction liquid is filtered, washed and dried to obtain the self-lubricating microcapsules; Wherein, the surfactant is a mixture of sorbitan monopalmitate and sodium lauryl sulfate in a mass ratio of 2:1; The lubricating oil composition is a mixture of perfluoropolyether and 1-ethyl-3-methylimidazolium tetrafluoroborate in a mass ratio of 1.5:1; the molecular weight of the perfluoropolyether is 3000-4000; The monomer mixture comprises ethyl methacrylate, styrene and butyl acrylate, and the mass ratio of ethyl methacrylate, styrene and butyl acrylate is 5:2:1; The crosslinking agent is trimethylolpropane triacrylate; and the initiator is ammonium persulfate.

[0041] Example 2 A self-lubricating microcapsule, the preparation method of which comprises the following steps: 200 parts of deionized water and 3 parts of surfactant were mixed under heating in a water bath, and then 40 parts of lubricating oil composition were added while stirring, and stirred for 30 minutes; 12 parts of the monomer mixture, 0.05 parts of the cross-linking agent and 0.5 parts of the initiator were added in sequence, and the mixture was reacted at 75-80° C. for 8 hours to obtain a reaction solution; The reaction liquid is filtered, washed and dried to obtain the self-lubricating microcapsules; Wherein, the surfactant is a mixture of sorbitan monopalmitate and sodium lauryl sulfate in a mass ratio of 2:1; The lubricating oil composition is a mixture of perfluoropolyether and 1-ethyl-3-methylimidazolium tetrafluoroborate in a mass ratio of 1.5:1; the molecular weight of the perfluoropolyether is 3000-4000; The monomer mixture comprises ethyl methacrylate, styrene and butyl acrylate, and the mass ratio of ethyl methacrylate, styrene and butyl acrylate is 5:2:1; The crosslinking agent is trimethylolpropane triacrylate; and the initiator is ammonium persulfate.

[0042] Example 3 A self-lubricating microcapsule, the preparation method thereof comprises the following steps, calculated by weight: 200 parts of deionized water and 3 parts of surfactant were mixed under heating in a water bath, and then 40 parts of lubricating oil composition were added while stirring, and stirred for 30 minutes; Add 10 parts of the monomer mixture, 0.1 parts of the crosslinking agent and 0.5 parts of the initiator, and react at 75-80° C. for 8 hours to obtain a reaction solution; The reaction liquid is filtered, washed and dried to obtain the self-lubricating microcapsules; Wherein, the surfactant is a mixture of sorbitan monopalmitate and dodecyltrimethylammonium chloride in a mass ratio of 1:1; The lubricating oil composition is a mixture of perfluoropolyether and 1-ethyl-3-methylimidazolium tetrafluoroborate in a mass ratio of 1.2:1; the molecular weight of the perfluoropolyether is 3000-4000; The monomer mixture comprises ethyl methacrylate, styrene and butyl acrylate, and the mass ratio of ethyl methacrylate, styrene and butyl acrylate is 4:2:1; The crosslinking agent is trimethylolpropane triacrylate; and the initiator is ammonium persulfate.

[0043] Example 4 A self-lubricating microcapsule, which is different from Example 1 in that, in the monomer mixture, the mass ratio of ethyl methacrylate, styrene and butyl acrylate is 4:2:3.

[0044] Example 5 A self-lubricating microcapsule, the preparation method of which is different from that of Example 1 in that the mass ratio of the perfluoropolyether to the ionic liquid is 2:1.

[0045] Example 6 A self-lubricating microcapsule, the preparation method of which is different from that of Example 1 in that the mass ratio of the perfluoropolyether to the ionic liquid is 1:1.

[0046] Example 7 A self-lubricating microcapsule, the preparation method of which is different from that of Example 1 in that 1-octylimidazole tetrafluoroborate is used to replace 1-ethyl-3-methylimidazole tetrafluoroborate.

[0047] Comparative Example 1 A self-lubricating microcapsule, the preparation method of which is different from that of Example 1 in that butyl acrylate is not used in the monomer mixture.

[0048] Comparative Example 2 A self-lubricating microcapsule, the preparation method of which is different from that of Example 1 in that ethyl methacrylate is not used in the monomer mixture.

[0049] Comparative Example 3 A self-lubricating microcapsule, the preparation method of which is different from that of Example 1 in that acrylamide is used to replace styrene in the monomer mixture.

[0050] The structure of the self-lubricating microcapsules prepared in Example 1 was observed using a transmission electron microscope. Figure 1 As shown, combined Figure 1-Figure 4 It can be seen from the results that the self-lubricating microcapsules prepared in Example 1 have an obvious core-shell structure. Figure 2-Figure 4 These are the distribution diagrams of C, O and F elements in the self-lubricating microcapsules. From the distribution diagram of F element, it can be seen that it is obviously distributed in the inner cavity of the microcapsules. The F element mainly comes from perfluoropolyether, while C and O elements are largely involved in forming the shell structure, corresponding to a variety of monomers and cross-linking agents.

[0051] Figure 5 and Figure 6 They are respectively digital photos and scanning electron microscope pictures of the self-lubricating microcapsules prepared in Example 1. As can be seen from the figures, the self-lubricating microcapsules prepared in Example 1 are spherical, have good structure, and good uniformity. Figure 7 This is a particle size distribution diagram of the self-lubricating microcapsules prepared in Example 1. From the results in the figure, it can be seen that the particle sizes of the self-lubricating microcapsules are mainly concentrated in the range of 0.2 to 1.2 microns.

[0052] The self-lubricating microcapsules prepared in the above examples and comparative examples were used to prepare polymer composite coatings, and a coating without adding the self-lubricating microcapsules was set as a blank group.

[0053] The friction properties of each coating were measured and the corresponding test results are shown in Table 1.

[0054] The coating preparation method is as follows: Water-based polyurethane emulsion, anionic, provided by Jining Huakai Resin Co., Ltd., transparent in appearance, solid content of 30%, viscosity of 75cps, pH value of 10.0, density of 1.054g / cm 3 .

[0055] First, add 300g of water-based polyurethane emulsion, 10g of self-lubricating microcapsules, and 0.5g of surfactant cetyltrimethylammonium bromide into a stirring device, stir evenly to obtain a mixture; perform vacuum degassing on the mixture, and fully mix it, control the vacuum degree at 0.1MPa, continue for 30min and stand for 10min to obtain a coating; evenly apply the coating on a Q235 steel sheet substrate, and then heat it in a blast drying oven at 60°C for 4 hours for curing to obtain a coating.

[0056] To determine the friction properties of the coating, a repeated mode friction test was performed on a UMT friction tester, with the grinding head made of bearing steel CCr15, a loading force of 5N, a test time of 1 hour, a frequency of 8Hz, and a distance of 10mm.

[0057] After the friction coefficient test, the worn sample was transferred to the white light interferometer, and the wear rate of the sample was calculated by observing and analyzing the worn surface. The data obtained in Table 1 are the average values ​​of at least three successfully tested samples.

[0058] Table 1 Friction properties of polymer coatings containing self-lubricating microcapsules

[0059] From the above results and Figure 8 It can be seen from the results that, compared with the blank group, the coatings prepared using the self-lubricating microcapsules of Examples 1-7 have a low friction coefficient and a significantly reduced wear rate, reflecting that the self-lubricating microcapsules of the present invention can effectively play a lubricating role.

[0060] Please refer to Table 1. Figure 8 and Fig. 9 Compared with Example 1, the self-lubricating microcapsules of Example 1 do not use butyl acrylate, and the self-lubricating microcapsules of Example 2 do not use ethyl methacrylate. From the results, the friction coefficient and wear rate of the coatings prepared by the two are higher. The reason is that the reduction of butyl acrylate or ethyl methacrylate will cause the shell structure strength of the self-lubricating microcapsules to decrease, making them more prone to rupture. When in use, the premature release of the lubricating component will affect the lubrication effect.

[0061] Please refer to Table 1. Figure 8 and Fig. 9 Compared with Example 1, Comparative Example 3 uses acrylamide to replace styrene. From the results, the friction performance of Comparative Example 3 is obviously reduced, reflecting that the choice of monomer will also affect the shell structure strength of the self-lubricating microcapsule and further affect its use effect.

[0062] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. A self-lubricating microcapsule, characterized in that: The raw materials for its preparation include, by weight: 38-42 parts of lubricating oil composition, 8-12 parts of monomer mixture, 3-4 parts of surfactant, 0.5-1 part of initiator, 0.05-0.15 part of crosslinking agent and 180-220 parts of deionized water; the monomer mixture includes ethyl methacrylate, styrene and butyl acrylate.

2. The self-lubricating microcapsule according to claim 1, characterized in that The lubricating oil composition comprises perfluoropolyether and ionic liquid.

3. The self-lubricating microcapsule according to claim 2, characterized in that: The ionic liquid includes at least one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-octylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium hexafluorophosphate, and trihexyl (tetradecyl) phosphine diisooctyl phosphate.

4. The self-lubricating microcapsule according to claim 2, characterized in that: The mass ratio of the perfluoropolyether to the ionic liquid is (1.2-1.5):

1.

5. The self-lubricating microcapsule according to claim 1, characterized in that: The mass ratio of the ethyl methacrylate, styrene and butyl acrylate is (4-5):(2-1):

1.

6. The self-lubricating microcapsule according to claim 1, characterized in that: The surfactant includes a nonionic surfactant and a reactive surfactant.

7. The self-lubricating microcapsule according to claim 6, characterized in that: The nonionic surfactant includes at least one of sorbitan monolaurate, sorbitan monopalmitate, and sorbitan monostearate; the reactive surfactant includes at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and dodecyltrimethylammonium chloride.

8. The self-lubricating microcapsule according to claim 1, characterized in that: The crosslinking agent includes at least one of allyl methacrylate, trimethylolpropane triacrylate, ethyl acetoacetate methacrylate, ethylene glycol diacrylate, and 1,4-butanediol diacrylate.

9. A method for preparing microcapsules, characterized in that: The method for preparing the self-lubricating microcapsule according to any one of claims 1 to 8 comprises the following steps: Mix deionized water and surfactant in a water bath, then add the lubricating oil composition while stirring, and stir for 20 to 30 minutes; Adding a monomer mixture, a crosslinking agent and an initiator in sequence, reacting at 75 to 80° C. for 8 to 10 hours to obtain a reaction solution; The reaction liquid is filtered, washed and dried to obtain the self-lubricating microcapsules.

10. Use of the self-lubricating microcapsule according to any one of claims 1 to 8 as a lubricant in polymer materials.

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