A silicone-based temperature-resistant lubricating coating and a method for preparing the same

Abstract

The present application relates to the technical field of silicone coating, in particular to a silicone resin-based temperature-resistant lubricating coating and a preparation method thereof.The present application provides a silicone resin-based temperature-resistant lubricating coating, which takes temperature-resistant silicone resin as a matrix, cooperates with high-temperature-resistant lubricating fillers, solvents and additives, realizes the comprehensive improvement of the high-temperature resistance, lubricity, adhesion and toughness of the coating through component synergy and process optimization, and is simple in preparation process, suitable in cost and suitable for industrialized production.The present application takes temperature-resistant silicone resin as a high-temperature stable organic-inorganic hybrid bonding phase, through the complementary lubrication of the layered structure of the high-temperature-resistant lubricating fillers, the wide-temperature-range functional matching and the antioxidation synergistic protection, a composite coating system which can continuously provide low-friction and long-life lubricating effect in the range from room temperature to high temperature is constructed.

Description

Technical Field

[0001] This invention relates to the field of silicone resin coating technology, and in particular to a silicone resin-based high-temperature resistant lubricating coating and its preparation method. Background Technology

[0002] In aerospace, machinery manufacturing, and high-temperature equipment fields, components are often subjected to harsh conditions of high temperature, high load, and high speed operation, placing extremely high demands on the high-temperature resistance, lubrication performance, and adhesion of surface lubrication and protective coatings. However, current lubrication coatings on the market suffer from numerous technical bottlenecks, making it difficult to meet the needs of high-end equipment: most coatings can only maintain a long-term operating temperature below 300℃, and above this temperature, they are prone to thermal degradation, carbonization, and failure; they have a high coefficient of friction, resulting in poor lubrication; they have weak adhesion to the substrate, making them prone to peeling and flaking under long-term high-temperature environments; and after high-temperature curing, they have poor toughness, are prone to hardening and cracking, and significantly shorten their service life.

[0003] Organosilicon resins, with their unique Si-O-Si main chain structure and bond energies far exceeding those of carbon-based organic resins, exhibit excellent thermal stability, oxidation resistance, and chemical inertness. Compared to traditional carbon-chain resins, organosilicon resins demonstrate superior structural stability at high temperatures. Upon thermal decomposition of the side groups, they form a highly cross-linked, dense Si-O-Si protective layer, further blocking heat transfer and the intrusion of corrosive media. Simultaneously, they combine the heat resistance of inorganic materials with the mechanical flexibility of organic polymers, making them excellent matrix materials for preparing high-performance, heat-resistant functional coatings.

[0004] In recent years, although research on silicone resin lubricating coatings has made some progress, a common challenge remains in balancing performance. Either improved lubrication performance is compromised by reduced temperature resistance and adhesion, or improved toughness is lost while maintaining lubrication effectiveness. Furthermore, some processes are complex and costly, hindering large-scale industrial applications. Therefore, developing a lubricating coating that combines excellent high-temperature resistance, lubrication, adhesion, and toughness, while also being easy to prepare and cost-effective, has become a pressing technical problem in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing high-temperature lubricating coatings, such as insufficient high-temperature resistance, poor lubrication effect, weak adhesion to the substrate, easy cracking at high temperatures, and complex processes, and to provide a silicone resin-based high-temperature resistant lubricating coating and its preparation method. The coating of this invention uses a high-temperature resistant silicone resin as the matrix, combined with high-temperature resistant lubricating fillers, solvents, and additives. Through component synergy and process optimization, the coating's high-temperature resistance, lubricity, adhesion, and toughness are comprehensively improved. Furthermore, the preparation process is simple, cost-effective, and suitable for industrial production.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: One of the technical solutions of this invention provides a silicone resin-based high-temperature resistant lubricating coating, wherein the raw materials, by weight, include: Heat-resistant silicone resin: 5-20 parts; High-temperature resistant lubricating filler: 5-40 parts; Solvent: 10-60 parts; Additives: 0.1–5 parts; The heat-resistant silicone resin is prepared from two or more of the following: methylphenyldiethoxysilane, phenyltriethoxysilane, dimethyldiethoxysilane, methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, ethyltriethoxysilane, and diphenyldiethoxysilane.

[0007] The second technical solution of the present invention provides a method for preparing the above-mentioned silicone resin-based high-temperature resistant lubricating coating, comprising the following steps: Coating preparation: Grind and disperse the high-temperature resistant lubricating filler, then add the heat-resistant silicone resin, solvent and additives, and stir to obtain the coating; Coating and curing: The coating is applied to the surface of the substrate and cured to obtain the silicone resin-based high-temperature lubricating coating.

[0008] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a heat-resistant silicone resin as a high-temperature stable organic-inorganic hybrid binder. Through complementary lubrication via the layered structure of the high-temperature resistant lubricating filler, wide-temperature-range functional matching, and synergistic antioxidant protection, a composite coating system is constructed that continuously provides low-friction, long-life lubrication effects across a range from room temperature to high temperatures. The heat-resistant silicone resin, as the binder phase, has a Si-O-Si inorganic backbone with a bond energy as high as 444 kJ / mol, far exceeding that of a C-C bond (347 kJ / mol), thus endowing the coating with excellent thermal stability. Furthermore, by introducing organic side groups with higher thermal stability, such as phenyl groups, the heat-resistant silicone resin can further improve its thermal decomposition temperature and char residue, while simultaneously adjusting its flexibility and crosslinking density. During the heating and curing process, the silanol groups (Si-OH) in the silicone resin undergo a condensation reaction, forming a three-dimensional network structure, which imparts excellent mechanical strength, adhesion, and density to the coating. In addition, under high-temperature conditions, the organic side groups gradually decompose, but the Si-O backbone can still be retained and partially transformed into a silicon-oxygen ceramic structure, thereby maintaining the integrity of the coating and its ability to encapsulate the lubricating filler. The process of this invention is simple and controllable, the synthesis and coating process is simple, no special equipment is required, the cost is moderate, and it is suitable for large-scale production and promotion.

[0009] The silicone resin-based high-temperature resistant lubricating coating provided by the present invention has the following advantages: (1) Excellent high temperature resistance: the coating can be used for a long time in a high temperature environment of 500℃ without degradation, carbonization or powdering; (2) Outstanding lubrication and friction reduction effect: the compound solid lubricating components have a low coefficient of friction and good wear resistance, effectively reducing component wear; (3) Strong adhesion and stability: it is firmly bonded to metal, ceramic and other substrates, and does not crack or fall off under high temperature conditions. Attached Figure Description

[0010] Figure 1 Scanning electron microscope image of the silicone resin-based high-temperature lubricating coating prepared in Example 1; Figure 2 The infrared spectra of the heat-resistant silicone resin before and after curing in Example 1 are shown, where (a) is before curing and (b) is after curing. Figure 3 The TG curve of the heat-resistant silicone resin in Example 1 after curing under air conditions; Figure 4 The adhesion test results are for the silicone resin-based high-temperature lubricating coating prepared in Example 1; Figure 5 The results show the flexibility test results of the silicone resin-based high-temperature lubricating coating prepared in Example 1. Figure 6 The impact resistance test results are for the front and back sides of the silicone resin-based high-temperature lubricating coating prepared in Example 1. Figure 7 The images show the comparison of the silicone resin-based high-temperature resistant lubricating coating prepared in Example 1 before and after aging at 500°C for 10 hours. (a) is before aging, and (b) is after aging. Figure 8 The friction coefficient variation curves of the silicone resin-based high-temperature resistant lubricating coating prepared in Example 1 when combined with Al2O3 ceramic balls at different temperatures are shown, where (a) is 25℃, (b) is 100℃, and (c) is 500℃. Detailed Implementation

[0011] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0012] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0013] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0014] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0015] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0016] All raw materials used in this invention can be obtained commercially or prepared using existing technologies.

[0017] This invention provides a silicone resin-based high-temperature resistant lubricating coating, comprising, by weight parts: 5-20 parts of high-temperature resistant silicone resin; 5-40 parts of high-temperature resistant lubricating filler; 10-60 parts of solvent; and 0.1-5 parts of additives; more preferably: 5-10 parts of high-temperature resistant silicone resin; 7-10 parts of high-temperature resistant lubricating filler; 50-60 parts of solvent; and 1-5 parts of additives.

[0018] In this invention, the heat-resistant silicone resin is prepared from two or more of the following: methylphenyldiethoxysilane, phenyltriethoxysilane, dimethyldiethoxysilane, methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, ethyltriethoxysilane, and diphenyldiethoxysilane. Different combinations and proportions of silane monomers in this invention result in different alkane-to-silane ratios and phenyl content in the prepared silicone resin, thereby affecting the flexibility, adhesion, and heat resistance of the silicone resin.

[0019] In a preferred embodiment of the present invention, the heat-resistant silicone resin is prepared from methylphenyldiethoxysilane, methyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; the ratio of the amounts of methylphenyldiethoxysilane, methyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane is (31.5-42) parts: (40.05-53.4) parts: (8.85-11.8) parts.

[0020] In this invention, the preparation method of the heat-resistant silicone resin includes: adding silane monomers to a solvent system and carrying out a co-hydrolysis-condensation reaction in the presence of water and a catalyst to obtain the heat-resistant silicone resin.

[0021] In this invention, during the preparation of the heat-resistant silicone resin, the solvent system consists of xylene and anhydrous ethanol.

[0022] In the preparation process of the heat-resistant silicone resin, the catalyst is an acid catalyst or a base catalyst; the acid catalyst is selected from phosphoric acid; the base catalyst is selected from potassium hydroxide.

[0023] In the preparation process of the heat-resistant silicone resin, the temperature of the co-hydrolysis-condensation reaction is 40-160°C and the reaction time is 2-15h; the co-hydrolysis-condensation reaction is further preferably carried out at 60°C for 7h and then heated to 150°C for 1.5h.

[0024] In the preparation process of the heat-resistant silicone resin, the co-hydrolysis-condensation reaction is followed by a distillation step; the distillation temperature is 150°C and the distillation time is 2 hours.

[0025] In this invention, the high-temperature resistant lubricating filler is selected from one or more of graphite, fluorinated graphite, molybdenum disulfide, tungsten disulfide, boron nitride, polytetrafluoroethylene micro powder, talc, antimony trioxide, and mica, and is more preferably selected from graphite, molybdenum disulfide, and antimony trioxide; the ratio of graphite, molybdenum disulfide, and antimony trioxide is (4.27-5.49) parts: (1.1-2.56) parts: (0.85-1.1) parts. Graphite has strong covalent bonds within its carbon atom layers and relatively weak van der Waals forces between the layers, making it prone to slippage under shear stress; simultaneously, graphite can adsorb water vapor or oxygen molecules in humid or oxygen-containing environments, reducing interlayer bonding forces and further promoting lubrication. Molybdenum disulfide (MoS2) has a hexagonal layered, S-Mo-S three-layer sandwich structure with strong covalent bonds within the layers and weak van der Waals forces between the layers. It has low interlayer shear strength and preferentially undergoes interlayer slip under stress to form a low-friction transfer film. It has excellent lubrication performance from room temperature to 300℃, and its oxidation can be slowed down under high-temperature conditions when coated with silicone resin.

[0026] In this invention, the solvent is selected from one or more of aromatic solvents, alcohol solvents, ester solvents, ether alcohol solvents and ketone solvents.

[0027] In this invention, the aromatic solvent is selected from one or more of toluene, xylene, and trimethylbenzene; the alcohol solvent is selected from one or more of ethanol, isopropanol, n-butanol, and isobutanol; the ester solvent is selected from one or more of ethyl acetate, butyl acetate, and propyl acetate; the ether alcohol solvent is selected from one or more of ethylene glycol monobutyl ether and propylene glycol methyl ether; and the ketone solvent is selected from one or more of acetone, butanone, and methyl isobutyl ketone.

[0028] In this invention, the additive is selected from one or more of dispersants, leveling agents and defoamers.

[0029] The present invention also provides a method for preparing the above-mentioned silicone resin-based high-temperature resistant lubricating coating, comprising the following steps: Coating preparation: Grind and disperse the high-temperature resistant lubricating filler, then add the heat-resistant silicone resin, solvent and additives, and stir to obtain the coating; Coating and curing: The coating is applied to the surface of the substrate and cured to obtain the silicone resin-based high-temperature lubricating coating.

[0030] In this invention, the curing temperature is 120-350℃ and the curing time is 2-6h; the curing is further preferably: pretreatment at 120℃ for 1h, treatment at 200℃ for 4h, and the heating rate is 5℃ / min.

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] The testing method for the following embodiments is as follows: Flexibility test: Refer to GB / T1731 "Determination of Flexibility of Paint Film and Putty Film"; Adhesion test: Refer to GB / T1720 "Determination of Adhesion of Paint Films"; Impact resistance test: Refer to GB / T1732 "Determination of impact resistance of paint film"; Tribological properties: friction time 60 min, load 5 N, rotation speed 300 r / min, equipment is HT-1000 high temperature friction and wear testing machine (purchased from Lanzhou Zhongke Kaihua Technology Development Co., Ltd.).

[0033] In the following examples, each portion is calculated as 1g.

[0034] Example 1 A silicone resin-based high-temperature resistant lubricating coating, comprising, by weight, the following raw materials: Heat-resistant silicone resin: 10 parts, prepared from 31.5 parts methylphenyldiethoxysilane, 40.05 parts methyltriethoxysilane and 8.85 parts γ-glycidoxypropyltrimethoxysilane. The molar ratio of alkyl to phenyl in the heat-resistant silicone resin is 2.75:1, and the molar ratio of the total molar amount of alkyl and phenyl to silicon is 1.4:1. High-temperature resistant lubricating filler: 7.68 parts, composed of 4.27 parts graphite, 2.56 parts MoS2 and 0.85 parts Sb2O3; Solvent: 50.77 parts, consisting of 11.54 parts toluene and 39.23 parts anhydrous ethanol; Additives: 1 part, consisting of 0.5 parts leveling agent 410 and 0.5 parts defoamer 902W; The preparation process of the heat-resistant silicone resin is as follows: 20.1 g xylene, 20.1 g anhydrous ethanol, 31.5 g methylphenyl diethoxysilane, 40.05 g methyltriethoxysilane, and 8.85 g γ-glycidoxypropyltrimethoxysilane are added to a three-necked flask to obtain mixed solution 1, and mechanical stirring is started. Mixed solution 1 is heated to 60°C, and then 35.1 g of phosphoric acid aqueous solution (the mass content of phosphoric acid in the phosphoric acid aqueous solution is 1%) is added dropwise to mixed solution 1 to obtain mixed solution 2. Mixed solution 2 is refluxed at 60°C for 7 h, then heated to 150°C and refluxed for 1.5 h, and finally distilled at 150°C for 2 h to obtain 41.8 g methylphenyl silicone resin, i.e., the heat-resistant silicone resin.

[0035] The preparation method of the above-mentioned silicone resin-based high-temperature resistant lubricating coating includes the following steps: Coating preparation: 4.27g graphite, 2.56g MoS2, 0.85g Sb2O3, 0.5g leveling agent 410, 0.5g defoamer 902W and 11.54g toluene were added to a conical mill and ground twice. Then, it was mixed with 10g heat-resistant silicone resin and 39.23g anhydrous ethanol and dispersed at 10000r / min for 3min using a high-speed shear disperser to obtain a silicone resin-based heat-resistant lubricating coating. Coating and curing: The silicone resin-based high-temperature resistant lubricating coating is uniformly sprayed onto the substrate using a spray gun, pretreated at 120℃ for 1 hour, treated at 200℃ for 4 hours, with a heating rate of 5℃ / min, to obtain the silicone resin-based high-temperature resistant lubricating coating.

[0036] The results showed that the silicone resin-based high-temperature lubricating coating prepared in Example 1 had a flexibility of 1 mm, an adhesion grade of 1, an impact resistance of 100 cm, and a friction coefficient that remained stable at 0.19 after 60 min of friction under a 5 N load. After 10 h of heat preservation at 500 °C, the coating showed no peeling or cracking and no color change.

[0037] Figure 1This is a scanning electron microscope image of the silicone resin-based high-temperature resistant lubricating coating prepared in Example 1. Figure 1 It can be seen that the silicone resin-based high-temperature lubricating coating prepared in Example 1 has good density and can be uniformly covered on the substrate.

[0038] Figure 2 The images show the infrared spectra of the heat-resistant silicone resin before and after curing in Example 1, where (a) is before curing and (b) is after curing. Figure 2 As shown in section (a), the silicone resin was 3396 cm² before curing. -1 The broad peak at 2970 cm⁻¹ is the absorption peak of the stretching vibration of Si-OH association. -1 The absorption peak at 1430 cm⁻¹ represents the stretching vibration of the CH bond in Si-CH₃. -1 The peak at 1000 cm⁻¹ represents the absorption peak of the aromatic ring vibration in Si-C₆H₅. -1 ~1120cm -1 A broad and strong absorption band is observed, which is the antisymmetric stretching vibration peak of Si-O-Si, a characteristic absorption peak of organosilicon resins. This indicates that methylphenyl silicone resin has been successfully prepared. Figure 2 As shown in section (b), the cured silicone resin is 3396 cm³. -1 The absorption peak disappears at this point. The group corresponding to this peak is Si-OH. The main reason is that during the curing process, the silanol groups (Si-OH) on the molecular chain undergo a dehydration condensation reaction. The Si-OH groups of adjacent molecular chains form new Si-O-Si covalent bonds by removing one molecule of water, which crosslinks the linear or branched molecular chains into a three-dimensional network structure. This change directly reflects that the resin forms a dense Si-O-Si network structure through crosslinking.

[0039] Figure 3 This is the TG curve of the heat-resistant silicone resin in Example 1 after curing under air conditions. From... Figure 3 As can be seen from this, the temperature T with a 5% mass loss of the heat-resistant silicone resin is... 5% Approaching 400℃, while the temperature of 10% mass loss is T. 10% It even reaches 480℃. Furthermore, the mass loss is very small after 700℃, indicating that the thermal decomposition reaction of silicone resin is close to complete.

[0040] Figure 4 The adhesion test results are for the silicone resin-based high-temperature lubricating coating prepared in Example 1. Figure 4 The results show that the silicone resin-based high-temperature lubricating coating prepared in Example 1 has excellent adhesion, reaching grade 1.

[0041] Figure 5 The results show the flexibility test results of the silicone resin-based high-temperature lubricating coating prepared in Example 1. Figure 5The results show that the silicone resin-based high-temperature lubricating coating prepared in Example 1 has excellent flexibility, reaching 1 mm.

[0042] Figure 6 The impact resistance test results for the front and back sides of the silicone resin-based high-temperature lubricating coating prepared in Example 1 are shown. Figure 6 The results show that the silicone resin-based high-temperature lubricating coating prepared in Example 1 has excellent impact resistance, up to 100 cm.

[0043] Figure 7 The images show a comparison of the silicone resin-based high-temperature resistant lubricating coating prepared in Example 1 before and after aging at 500℃ for 10 hours. (a) shows the coating before aging, and (b) shows the coating after aging. Figure 7 It can be seen that the appearance and color of the silicone resin-based high-temperature lubricating coating prepared in Example 1 did not change significantly before and after aging at 500℃.

[0044] Figure 8 The figures show the friction coefficient variation curves of the silicone resin-based high-temperature resistant lubricating coating prepared in Example 1 when combined with Al2O3 ceramic balls at different temperatures, where (a) is 25℃, (b) is 100℃, and (c) is 500℃. Figure 8 It can be seen that the average friction coefficient of the coating is less than 0.2 in the range of 25℃ to 500℃, and the wear life exceeds 60 minutes.

[0045] Example 2 A silicone resin-based high-temperature resistant lubricating coating, comprising, by weight, the following raw materials: Heat-resistant silicone resin: 10 parts, prepared from 31.5 parts methylphenyldiethoxysilane, 40.05 parts methyltriethoxysilane and 8.85 parts γ-glycidoxypropyltrimethoxysilane. The molar ratio of alkyl to phenyl in the heat-resistant silicone resin is 2.75:1, and the molar ratio of the total molar amount of alkyl and phenyl to silicon is 1.4:1. High-temperature resistant lubricating filler: 7.69 parts, composed of 5.49 parts graphite, 1.1 parts MoS2 and 1.1 parts Sb2O3; Solvent: 50.77 parts, consisting of 11.54 parts toluene and 39.23 parts anhydrous ethanol; Additives: 1 part, consisting of 0.5 parts leveling agent 410 and 0.5 parts defoamer 902W; The preparation process of the heat-resistant silicone resin is the same as in Example 1; The preparation method of the above-mentioned silicone resin-based high-temperature resistant lubricating coating includes the following steps: Coating preparation: 5.49g graphite, 1.1g MoS2, 1.1g Sb2O3, 0.5g leveling agent 410, 0.5g defoamer 902W and 11.54g toluene were added to a conical mill and ground twice. Then, it was mixed with 10g heat-resistant silicone resin and 39.23g anhydrous ethanol and dispersed at 10000r / min for 3min using a high-speed shear disperser to obtain a silicone resin-based heat-resistant lubricating coating. Coating and curing: The silicone resin-based high-temperature resistant lubricating coating is uniformly sprayed onto the substrate using a spray gun, pretreated at 120℃ for 1 hour, treated at 200℃ for 4 hours, with a heating rate of 5℃ / min, to obtain the silicone resin-based high-temperature resistant lubricating coating.

[0046] The results showed that the silicone resin-based high-temperature lubricating coating prepared in Example 2 had a flexibility of 1 mm, an adhesion grade of 1, an impact resistance of 100 cm, and a friction coefficient that remained stable at 0.13 after 60 min of friction under a 5 N load. After 10 h of heat treatment at 500 °C, the coating showed no peeling or cracking and no color change.

[0047] Example 3 A silicone resin-based high-temperature resistant lubricating coating, comprising, by weight, the following raw materials: Heat-resistant silicone resin: 10 parts, prepared from 42 parts methylphenyldiethoxysilane, 53.4 parts methyltriethoxysilane and 11.8 parts γ-glycidoxypropyltrimethoxysilane. The molar ratio of alkyl to phenyl in the heat-resistant silicone resin is 1.83:1, and the molar ratio of the total molar amount of alkyl and phenyl to silicon is 1.5:1. High-temperature resistant lubricating filler: 7.68 parts, composed of 4.27 parts graphite, 2.56 parts MoS2 and 0.85 parts Sb2O3; Solvent: 50.77 parts, consisting of 11.54 parts toluene and 39.23 parts anhydrous ethanol; Additives: 1 part, consisting of 0.5 parts leveling agent 410 and 0.5 parts defoamer 902W; The preparation process of the heat-resistant silicone resin is as follows: 26.8 g xylene, 26.8 g anhydrous ethanol, 42 g methylphenyl diethoxysilane, 53.4 g methyltriethoxysilane, and 11.8 g γ-glycidyl etheroxypropyltrimethoxysilane were added to a three-necked flask to obtain mixed solution 1, and mechanical stirring was started. Mixed solution 1 was heated to 60°C, and then 35.1 g of phosphoric acid aqueous solution was added dropwise to mixed solution 1 to obtain mixed solution 2. Mixed solution 2 was refluxed at 60°C for 7 hours, then heated to 150°C and refluxed for 1.5 hours. Finally, it was distilled at 150°C to obtain 59.61 g methylphenyl silicone resin, i.e., the heat-resistant silicone resin.

[0048] The preparation method of the above-mentioned silicone resin-based high-temperature resistant lubricating coating includes the following steps: Coating preparation: 4.27g graphite, 2.56g MoS2, 0.85g Sb2O3, 0.5g leveling agent 410, 0.5g defoamer 902W and 11.54g toluene were added to a conical mill and ground twice. Then, it was mixed with 10g heat-resistant silicone resin and 39.23g anhydrous ethanol and dispersed at 10000r / min for 3min using a high-speed shear disperser to obtain a silicone resin-based heat-resistant lubricating coating. Coating and curing: The silicone resin-based high-temperature resistant lubricating coating is uniformly sprayed onto the substrate using a spray gun, pretreated at 120℃ for 1 hour, treated at 200℃ for 4 hours, with a heating rate of 5℃ / min, to obtain the silicone resin-based high-temperature resistant lubricating coating.

[0049] The results showed that the silicone resin-based high-temperature lubricating coating prepared in Example 3 had a flexibility of 1 mm, an adhesion grade of 1, an impact resistance of 100 cm, and a friction coefficient that remained stable at 0.15 after 60 min of friction under a 5 N load. After 10 h of heat treatment at 500 °C, the coating showed no peeling or cracking and no color change.

[0050] Example 4 A silicone resin-based high-temperature resistant lubricating coating, comprising, by weight, the following raw materials: Heat-resistant silicone resin: 10 parts, prepared from 42 parts methylphenyldiethoxysilane, 53.4 parts methyltriethoxysilane and 11.8 parts γ-glycidoxypropyltrimethoxysilane. The molar ratio of alkyl to phenyl in the heat-resistant silicone resin is 1.83:1, and the molar ratio of the total molar amount of alkyl and phenyl to silicon is 1.5:1. High-temperature resistant lubricating filler: 7.69 parts, composed of 5.49 parts graphite, 1.1 parts MoS2 and 1.1 parts Sb2O3; Solvent: 50.77 parts, consisting of 11.54 parts toluene and 39.23 parts anhydrous ethanol; Additives: 1 part, consisting of 0.5 parts leveling agent 410 and 0.5 parts defoamer 902W; The preparation process of the heat-resistant silicone resin is the same as in Example 3; The preparation method of the above-mentioned silicone resin-based high-temperature resistant lubricating coating includes the following steps: Coating preparation: 5.49g graphite, 1.1g MoS2, 1.1g Sb2O3, 0.5g leveling agent 410, 0.5g defoamer 902W and 11.54g toluene were added to a conical mill and ground twice. Then, it was mixed with 10g heat-resistant silicone resin and 39.23g anhydrous ethanol and dispersed at 10000r / min for 3min using a high-speed shear disperser to obtain a silicone resin-based heat-resistant lubricating coating. Coating and curing: The silicone resin-based high-temperature resistant lubricating coating is uniformly sprayed onto the substrate using a spray gun, pretreated at 120℃ for 1 hour, treated at 200℃ for 4 hours, with a heating rate of 5℃ / min, to obtain the silicone resin-based high-temperature resistant lubricating coating.

[0051] The results showed that the silicone resin-based high-temperature lubricating coating prepared in Example 4 had a flexibility of 1 mm, an adhesion grade of 1, an impact resistance of 100 cm, and a friction coefficient that remained stable at 0.12 after 60 min of friction under a 5 N load. After 10 h of heat treatment at 500 °C, the coating showed no peeling or cracking and no color change.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silicone resin-based high-temperature resistant lubricating coating, characterized in that, By weight, the raw materials include: Heat-resistant silicone resin: 5-20 parts; High-temperature resistant lubricating filler: 5-40 parts; Solvent: 10-60 parts; Additives: 0.1–5 parts; The heat-resistant silicone resin is prepared from two or more of the following: methylphenyldiethoxysilane, phenyltriethoxysilane, dimethyldiethoxysilane, methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, ethyltriethoxysilane, and diphenyldiethoxysilane.

2. The silicone resin-based high-temperature resistant lubricating coating according to claim 1, characterized in that, The preparation method of the heat-resistant silicone resin includes: adding silane monomers to a solvent system and carrying out a co-hydrolysis-condensation reaction in the presence of water and a catalyst to obtain the heat-resistant silicone resin.

3. The silicone resin-based high-temperature resistant lubricating coating according to claim 2, characterized in that, The temperature of the co-hydrolysis-condensation reaction is 40–160°C, and the reaction time is 2–15 h; the catalyst is an acid catalyst or a base catalyst.

4. The silicone resin-based high-temperature resistant lubricating coating according to claim 1, characterized in that, The high-temperature resistant lubricating filler is selected from one or more of graphite, molybdenum disulfide, tungsten disulfide, boron nitride, talc, antimony trioxide, and mica.

5. The silicone resin-based high-temperature resistant lubricating coating according to claim 4, characterized in that, The high-temperature resistant lubricating filler is selected from graphite, molybdenum disulfide, and antimony trioxide.

6. The silicone resin-based high-temperature resistant lubricating coating according to claim 1, characterized in that, The solvent is selected from one or more of aromatic solvents, alcohol solvents, ester solvents, ether alcohol solvents and ketone solvents.

7. The silicone resin-based high-temperature resistant lubricating coating according to claim 6, characterized in that, The aromatic solvent is selected from one or more of toluene, xylene, and trimethylbenzene; the alcohol solvent is selected from one or more of ethanol, isopropanol, n-butanol, and isobutanol; the ester solvent is selected from one or more of ethyl acetate, butyl acetate, and propyl acetate; the ether alcohol solvent is selected from one or more of ethylene glycol monobutyl ether and propylene glycol methyl ether; and the ketone solvent is selected from one or more of acetone, butanone, and methyl isobutyl ketone.

8. The silicone resin-based high-temperature resistant lubricating coating according to claim 1, characterized in that, The additives are selected from one or more of dispersants, leveling agents, and defoamers.

9. A method for preparing a silicone resin-based high-temperature resistant lubricating coating as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Coating preparation: Grind and disperse the high-temperature resistant lubricating filler, then add the heat-resistant silicone resin, solvent and additives, and stir to obtain the coating; Coating and curing: The coating is applied to the surface of the substrate and cured to obtain the silicone resin-based high-temperature lubricating coating.

10. The preparation method according to claim 9, characterized in that, The curing temperature is 120–350℃, and the curing time is 2–6 hours.

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