Self-lubricating coating, preparation method thereof and method for forming self-lubricating coating

Abstract

The invention provides a self-lubricating coating, a preparation method thereof and a method for forming a self-lubricating coating. The self-lubricating coating comprises the following components: 0.5-10% of microcapsules, 5-30% of modified regulation filler, 5-30% of conductive particles, 0.1-5% of a curing agent, 0.1-5% of an accelerant, 0.1-5% of benzoin, 0.1-5% of a flatting agent, 10-40% of titanium dioxide, 5-20% of fibers and the balance of matrix resin. A coating layer formed by electrostatic spraying of the self-lubricating paint has good antifriction wear resistance and fatigue resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of materials, and in particular relates to a self-lubricating coating and a preparation method thereof, and a method for forming a self-lubricating coating. Background Art

[0002] Metal materials and other types of materials will experience severe adhesion, friction and wear during long-term testing or service, and may even crack and break, affecting the service life of the equipment. Resin-based composite materials are a multiphase material composed of a resin matrix and various reinforcing materials and other fillers. Their performance is superior to that of a single material, effectively improving the shortcomings of a single resin matrix such as poor mechanical properties. They are currently a type of composite material with relatively mature technology and the most widely used. Due to the high wear and adhesion failure of metal materials during long-term testing, the good mechanical properties and lubrication properties of polymer composite multiphase materials are increasingly gaining widespread attention. Summary of the invention

[0003] In order to solve the above problems, the object of the present invention is to provide a self-lubricating coating and a preparation method thereof, and a method for forming a self-lubricating coating, wherein the coating has good friction reduction, wear resistance and fatigue resistance.

[0004] In order to achieve the above-mentioned purpose, the present invention provides a self-lubricating coating, which comprises, by mass percentage, 0.5-10% microcapsules, 5-30% modified and regulated fillers, 5-30% conductive particles, 0.1-5% curing agent, 0.1-5% accelerator, 0.1-5% benzoin, 0.1-5% leveling agent, 10-40% titanium dioxide, 5-20% fiber, and the balance is base resin.

[0005] According to a specific embodiment of the present invention, preferably, the mass percentage of the microcapsules is, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, more preferably, the mass percentage of the microcapsules is 2-6%.

[0006] According to a specific embodiment of the present invention, preferably, the mass percentages of the modified and regulated fillers and the conductive particles are, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, more preferably, the mass percentages of the modified and regulated fillers and the conductive particles are 10-20%, respectively.

[0007] According to a specific embodiment of the present invention, preferably, the mass percentages of the curing agent, accelerator, benzoin and leveling agent are, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, respectively. More preferably, the mass percentages of the curing agent, accelerator, benzoin and leveling agent are, for example, 1-3%, respectively.

[0008] According to a specific embodiment of the present invention, preferably, the mass percentage of the titanium dioxide is, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, and more preferably, the mass percentage of the titanium dioxide is 15-30%.

[0009] According to a specific embodiment of the present invention, preferably, in the composition of the self-lubricating coating, except for the base resin, the sum of the mass percentages of the remaining components is ≤50%.

[0010] According to a specific embodiment of the present invention, preferably, the microcapsule is composed of a core material and a shell wall, the core material includes one or a combination of two or more of base oil PAO, base oil 70SN, lubricating oil I-40, and tung oil, and the shell wall includes a matrix resin. The core material of the microcapsule is lubricating oil, which can improve the friction and lubrication performance of the coating and long-term fatigue wear.

[0011] According to a specific embodiment of the present invention, preferably, the particle size of the microcapsule is 10 μm-500 μm.

[0012] According to a specific embodiment of the present invention, preferably, the density of the microcapsules is 2 kg / m 3 Up to 10kg / m 3 .

[0013] According to a specific embodiment of the present invention, preferably, the shell wall thickness of the microcapsule is 2 μm-50 μm.

[0014] According to a specific embodiment of the present invention, preferably, the conductive particles include one or a combination of two or more of graphene, carbon nanotubes, and graphite. The conductive particles provide certain conductive properties for the mixed raw materials according to the principle of electrostatic spraying.

[0015] According to a specific embodiment of the present invention, preferably, the modified and regulated filler includes one or a combination of two or more of calcium carbonate, clay, kaolin, talc, asbestos, mica, carbon black, calcium sulfate, calcium sulfite, molybdenum disulfide, and boron nitride. The modified and regulated filler is added according to the different requirements of the composite coating material to improve wear resistance, impact resistance, strength and hardness, etc.

[0016] According to a specific embodiment of the present invention, preferably, the fiber includes one or a combination of two or more of carbon fiber, glass fiber, and polytetrafluoroethylene fiber.

[0017] The curing agent, accelerator, benzoin and leveling agent in the self-lubricating coating of the present invention are made of commonly used materials corresponding to the base resin, wherein the curing agent can be selected from, for example, formaldehyde, ammonium chloride or cyclohexanone dibutyl peroxide paste, the accelerator can be selected from zinc chloride, trimethyl phosphate or calcium ethylhexanoate, and the leveling agent can be selected from diacetone alcohol; titanium dioxide generally uses titanium dioxide powder.

[0018] According to a specific embodiment of the present invention, preferably, the composition of the self-lubricating coating further includes a dye, and the dye is proportioned according to the color requirements of a specific application. More preferably, the mass percentage of the dye is 10-40%, and further preferably 15-30%.

[0019] According to a specific embodiment of the present invention, preferably, the matrix resin includes a thermosetting resin and / or a thermoplastic resin; the thermosetting resin is selected from one or a combination of more than one of polyester resin, epoxy resin, acrylic resin, polyurethane, fluorine-containing resin, urea-formaldehyde resin, and phenolic resin; the thermoplastic resin is selected from one or a combination of more than one of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polycarbonate (PC), polyamide (PA), polyoxymethylene (POM), polyphenylene ether, polysulfone, and rubber.

[0020] The present invention also provides a method for preparing the self-lubricating coating, which comprises the following steps:

[0021] (1) mixing base resin, microcapsules, modified and regulated fillers, curing agent, conductive particles, titanium dioxide, accelerator, benzoin, leveling agent, and fiber;

[0022] (2) melt extrusion blending and cooling;

[0023] (3) crushing, grading and screening to obtain the self-lubricating coating.

[0024] According to a specific embodiment of the present invention, preferably, in step (2), the melting temperature is 80-300°C, and the specific melting temperature is mainly determined according to the curing temperature of different resins, for example, 80°C, 90°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C.

[0025] According to a specific embodiment of the present invention, preferably, in step (3), the particle size of the self-lubricating coating obtained is 1-50 μm (e.g., 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm), more preferably 5-15 μm. Powders with different particle sizes can be graded and selected for spraying according to different requirements of the coating.

[0026] According to a specific embodiment of the present invention, the above preparation method comprises the following specific steps:

[0027] (1) First, thermosetting resin or thermoplastic resin, modified and regulated filler, curing agent, conductive particles, titanium dioxide, accelerator, benzoin, leveling agent, fiber, and dye are uniformly mixed through a coating stirring system;

[0028] (2) using a twin-screw extruder to melt-extrude and blend the mixed material obtained in step (1) at a suitable temperature, using different melt extrusion temperatures according to different resin materials, extruding the sheet-shaped mixed material, and then cooling it to room temperature (16-25° C.);

[0029] (3) Then, the flaky mixed material is crushed and graded and sieved by an ultrafine grinding machine to obtain the self-lubricating coating.

[0030] The present invention also provides a method for forming a self-lubricating coating on the surface of a substrate, which adopts the self-lubricating coating to form the self-lubricating coating on the surface of the substrate through electrostatic spraying.

[0031] According to a specific embodiment of the present invention, preferably, the voltage of electrostatic spraying is 50-120V (e.g., 50V, 60V, 70V, 80V, 90V, 100V, 110V, 120V), and the current is 50-100A (e.g., 50A, 60A, 70A, 80A, 90A, 100A).

[0032] According to a specific embodiment of the present invention, preferably, the spraying distance of the electrostatic spraying is 100-400 mm (e.g., 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm).

[0033] According to a specific embodiment of the present invention, preferably, the air supply pressure for electrostatic spraying is 5-20Pa (e.g., 5Pa, 6Pa, 7Pa, 8Pa, 9Pa, 10Pa, 11Pa, 12Pa, 13Pa, 14Pa, 15Pa, 16Pa, 17Pa, 18Pa, 19Pa, 20Pa).

[0034] The present invention also provides a coating formed by the self-lubricating coating.

[0035] According to a specific embodiment of the present invention, preferably, the self-lubricating coating is formed by electrostatic spraying.

[0036] The coating obtained by the coating of the present invention is uniform and free of holes, and has good leveling and impact resistance. Due to the introduction of microcapsules and other modified and regulated fillers, the friction-reducing and wear-resistant properties of the regulated coating are effectively improved, and the hardness and long-term fatigue life of the coating are improved; the introduction of various fibers and microcapsules greatly improves the friction-reducing and wear-resistant properties of the coating, and provides a new method of wear resistance, fatigue resistance, and interface adhesion resistance for long-life and high-reliability service parts in high-end equipment such as aerospace, and is suitable for application in fastener structures and bolt structures with micro-wear and three-body wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of the preparation of self-lubricating coating;

[0038] Figure 2 It is a schematic diagram of the composition of the self-lubricating coating;

[0039] Figure 3 It is a spray coating photo;

[0040] Figure 4 It is the surface morphology of the spray coating;

[0041] Figure 5 It is the structural diagram of the test sample. DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0043] If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in the field or the product instructions are used. If the manufacturer of the equipment or instruments is not specified, they are all conventional products that can be purchased commercially.

[0044] The microcapsules used in the following examples (Ashland China, Captivates HC microcapsules) are formed by 901 polyester resin encapsulating lubricating oil PAO6, with a particle size of 100 μm, a film thickness of 10 μm, and a density of 5 kg / m 3 ; It can be prepared by conventional methods in the art, or by referring to the following method:

[0045] The lubricating oil PAO6, 901 unsaturated polyester resin monomer and curing agent are mixed to obtain an oil phase; the surfactant SDS is dispersed in water to obtain an aqueous phase; the oil phase and the aqueous phase are mixed to form an emulsion, and a catalyst is added to react to obtain the microcapsule.

[0046] Example 1

[0047] This embodiment provides a controllable anti-friction and wear-resistant polymer self-lubricating composite coating, which is formed by the following steps, as shown in the process Figure 1 As shown:

[0048] (1) First, 60 g of phenolic resin, 10 g of titanium dioxide, 15 g of dye (chromium oxide green, the same below), 2 g of microcapsules, 6 g of basalt fiber, 5 g of molybdenum disulfide, 0.8 g of curing agent (formaldehyde), 0.2 g of accelerator (zinc chloride), 0.5 g of benzoin, 0.5 g of leveling agent (diacetone alcohol, the same below), and 1.0 g of graphite were fully mixed;

[0049] (2) extruding the mixed material in sheet form through a twin-screw extruder at a melting temperature of 120° C. and then cooling the mixed material to room temperature;

[0050] (3) crushing and sieving the obtained tablet composite material (flaky mixed material) by an ultrafine grinding unit, and selecting powder with an average particle size of 10 μm for spraying;

[0051] (4) The electrostatic spraying voltage is 50V, the current is 80A, the spraying distance is 200mm, and the air supply pressure is 6Pa. After the above steps, an adjustable friction-reducing and wear-resistant polymer self-lubricating composite material coating is obtained, and its composition diagram is shown in FIG. Figure 2 As shown; the appearance of the obtained coating is shown in Figure 3 , the surface morphology is shown in Figure 4 .

[0052] Example 2

[0053] This embodiment provides a controllable friction-reducing and wear-resistant polymer self-lubricating composite coating, which is formed by the following steps:

[0054] (1) First, 60 g of urea-formaldehyde resin, 10 g of titanium dioxide, 15 g of dye, 2 g of microcapsules, 6 g of carbon fiber, 5 g of molybdenum disulfide, 0.8 g of curing agent (ammonium chloride), 0.2 g of accelerator (trimethyl phosphate), 0.5 g of benzoin, 0.5 g of leveling agent, and 1.0 g of graphite were fully mixed;

[0055] (2) extruding the mixed material in sheet form through a twin-screw extruder at a melting temperature of 150° C. and then cooling the mixed material to room temperature;

[0056] (3) crushing and sieving the obtained tablet composite material (flaky mixed material) by an ultrafine grinding unit, and selecting powder with an average particle size of 10 μm for spraying;

[0057] (4) The electrostatic spraying voltage is 60 V, the current is 80 A, the spraying distance is 180 mm, and the air supply pressure is 6 Pa. After the above steps, an adjustable friction-reducing and wear-resistant polymer self-lubricating composite material coating is obtained.

[0058] Example 3

[0059] This embodiment provides a controllable friction-reducing and wear-resistant polymer self-lubricating composite coating, which is formed by the following steps:

[0060] (1) First, 60 g of polyester resin, 10 g of titanium dioxide, 15 g of dye, 2 g of microcapsules, 6 g of basalt fiber, 4 g of molybdenum disulfide, 0.8 g of curing agent (cyclohexanone dibutyl peroxide paste), 0.2 g of accelerator (calcium ethylhexanoate), 0.5 g of benzoin, 0.5 g of leveling agent, and 1.0 g of graphite were thoroughly mixed;

[0061] (2) extruding the mixed material in sheet form through a twin-screw extruder at a melting temperature of 80° C. and then cooling the mixed material to room temperature;

[0062] (3) crushing and sieving the obtained tablet composite material (flaky mixed material) by an ultrafine grinding unit, and selecting powder with an average particle size of 10 μm for spraying;

[0063] (4) The electrostatic spraying voltage is 50 V, the current is 70 A, the spraying distance is 150 mm, and the air supply pressure is 6 Pa. After the above steps, an adjustable friction-reducing and wear-resistant polymer self-lubricating composite material coating is obtained.

[0064] Comparative Example 1

[0065] This comparative example provides a resin coating, which is formed by the following steps:

[0066] (1) First, 60 g of polyester resin, 15 g of titanium dioxide, 25 g of dye, 1.8 g of curing agent (cyclohexanone dibutyl peroxide paste), 1.2 g of accelerator (calcium ethylhexanoate), 0.5 g of benzoin, and 0.5 g of leveling agent were thoroughly mixed;

[0067] (2) extruding the mixed material in sheet form through a twin-screw extruder at a melting temperature of 80° C. and then cooling the mixed material to room temperature;

[0068] (3) crushing and sieving the obtained tablet composite material (flaky mixed material) by an ultrafine grinding unit, and selecting powder with an average particle size of 10 μm for spraying;

[0069] (4) Electrostatic spraying voltage is 50 V, current is 70 A, spraying distance is 150 mm, and air supply pressure is 6 Pa. After the above steps, a resin coating is obtained.

[0070] Comparative Example 2

[0071] This comparative example provides a resin coating, which is formed by the following steps:

[0072] (1) First, 70 g of polyester resin, 10 g of titanium dioxide, 10 g of dye, 5 g of curing agent (cyclohexanone dibutyl peroxide paste), 5 g of accelerator (calcium ethylhexanoate), 0.1 g of benzoin, and 0.1 g of leveling agent were thoroughly mixed;

[0073] (2) extruding the mixed material in sheet form through a twin-screw extruder at a melting temperature of 80° C. and then cooling the mixed material to room temperature;

[0074] (3) crushing and sieving the obtained tablet composite material (flaky mixed material) by an ultrafine grinding machine, and selecting powder with an average particle size of 10 μm for spraying;

[0075] (4) Electrostatic spraying voltage is 50 V, current is 70 A, spraying distance is 150 mm, and air supply pressure is 6 Pa. After the above steps, a resin coating is obtained.

[0076] Test plan: Spray the resin coating of Comparative Examples 1-2 or the adjustable friction-reducing and wear-resistant polymer self-lubricating composite coating of Examples 1-3 onto a sliding sleeve sample (such as Figure 5 As shown in the figure, unit is mm, material is stainless steel, thickness is 16 mm, round hole diameter is 16 mm), coating thickness is controlled to be 100-110 microns, according to aviation titanium alloy test standards (according to the axial loading fatigue SN curve of TB6 titanium alloy ear piece components in Volume 4 of the "China Aviation Materials Handbook"), MTS fatigue tests (Test Examples 3-7) are carried out, and the results are shown in Table 1.

[0077] Test Example 1

[0078] In this test example, the surface of the specimen was not treated in any way and the MTS fatigue test was performed. The results are shown in Table 1.

[0079] Test Example 2

[0080] The surface of the test specimen in this test example was subjected to conventional corundum sandblasting (the sandblasting particles used were 60# corundum particles, the sandblasting pressure was 60Pa, the angle was 30°, the distance was 100mm, and the sandblasting was 5min), and the MTS fatigue test was performed. The results are shown in Table 1.

[0081] Table 1

[0082] Test Case Specimen type Fatigue failure cycles Test Example 1 No surface treatment 94667 Test Example 2 Sandblasting only 139105 Test Example 3 Comparative Example 1 Coating 145260 Test Example 4 Comparative Example 2 Coating 523522 Test Example 5 Example 1 Coating 1068051 Test Example 6 Example 2 Coating 1276719 Test Example 7 Example 3 Coating 2043619

[0083] It can be seen from the results in Table 1 that, compared with the coating treatment (Test Examples 5 to 7), the fatigue life of the samples without coating treatment, only sandblasting treatment and coating treatment of Comparative Example 1 is more than 10 times different.

[0084] In the description of this specification, the description with reference to the term "embodiment" or the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0085] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A self-lubricating coating, which, calculated by mass percentage, comprises: 0.5-10% microcapsules, 5-30% modified and regulated fillers, 5-30% conductive particles, 0.1-5% curing agent, 0.1-5% accelerator, 0.1-5% benzoin, 0.1-5% leveling agent, 10-40% titanium dioxide, 5-20% fiber, and the balance is base resin.

2. The self-lubricating coating according to claim 1, wherein: The mass percentage of the microcapsules is 2-6%; Preferably, the mass percentages of the modified and regulated fillers and the conductive particles are 10-20% respectively; Preferably, the mass percentages of the curing agent, accelerator, benzoin and leveling agent are 1-3% respectively; Preferably, the mass percentage of the titanium dioxide is 15-30%.

3. The self-lubricating coating according to claim 1 or 2, wherein: In the composition of the self-lubricating coating, except for the base resin, the sum of the mass percentages of the other components is ≤50%.

4. The self-lubricating coating according to claim 1, wherein: The microcapsule is composed of a core material and a shell wall, wherein the core material comprises one or a combination of two or more of base oil PAO, base oil 70SN, lubricating oil I-40, and tung oil, and the shell wall comprises a matrix resin; Preferably, the particle size of the microcapsules is 10 μm-500 μm; Preferably, the density of the microcapsules is 2 kg / m 3 Up to 10kg / m 3 ; Preferably, the shell wall thickness of the microcapsule is 2 μm-50 μm.

5. The self-lubricating coating according to claim 1, wherein: The conductive particles include one or a combination of two or more of graphene, carbon nanotubes, and graphite; Preferably, the modified regulating filler includes one or a combination of two or more of calcium carbonate, clay, kaolin, talc, asbestos, mica, carbon black, calcium sulfate, calcium sulfite, molybdenum disulfide, and boron nitride; Preferably, the fiber includes one or a combination of two or more of carbon fiber, glass fiber, and polytetrafluoroethylene fiber.

6. The self-lubricating coating according to claim 1, wherein: The matrix resin includes a thermosetting resin and / or a thermoplastic resin; The thermosetting resin is selected from one or a combination of two or more of polyester resin, epoxy resin, acrylic resin, polyurethane, fluorine-containing resin, urea-formaldehyde resin and phenolic resin; The thermoplastic resin is selected from one or a combination of two or more of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyoxymethylene, polycarbonate, polyphenylene ether, polysulfone and rubber.

7. The method for preparing the self-lubricating coating according to any one of claims 1 to 6, comprising the following steps: (1) mixing base resin, microcapsules, modified and regulated fillers, curing agent, conductive particles, titanium dioxide, accelerator, benzoin, leveling agent, and fiber; (2) melt extrusion blending and cooling; (3) crushing, grading and screening to obtain the self-lubricating coating.

8. The preparation method according to claim 7, wherein: In step (2), the melting temperature is 80-300°C; Preferably, in step (3), the particle size of the self-lubricating coating obtained is 1-50 μm, more preferably 5-15 μm.

9. A method for forming a self-lubricating coating on a substrate surface, comprising electrostatically spraying the self-lubricating coating according to any one of claims 1 to 6 to form a self-lubricating coating on the substrate surface; Preferably, the voltage of electrostatic spraying is 50-120V and the current is 50-100A; Preferably, the spraying distance of electrostatic spraying is 100-400mm; Preferably, the air supply pressure for electrostatic spraying is 5-20Pa.

10. A coating formed by the self-lubricating coating according to any one of claims 1 to 6; Preferably, the self-lubricating coating is formed by electrostatic spraying.

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