Self-repairing type hard film anti-corrosion film-forming material for non-rotating part and preparation method of self-repairing type hard film anti-corrosion film-forming material

Abstract

The invention provides a self-repairing hard film anti-corrosion film-forming material for a non-rotating part and a preparation method of the self-repairing hard film anti-corrosion film-forming material. The self-repairing hard film anti-corrosion film-forming material is prepared from 25 to 40 parts of modified nano silicon dioxide, 30 to 50 parts of fluorine-containing polyurethane prepolymer, 5 to 10 parts of microencapsulation corrosion inhibitor, 0.5 to 3 parts of graphene nanosheet and 25 to 35 parts of mixed solvent of propylene glycol methyl ether acetate and isophorone. By compounding the modified nano silicon dioxide, the fluorine-containing polyurethane prepolymer and the microencapsulation corrosion inhibitor, a compact protective coating with high hardness (greater than or equal to 2H) and excellent adhesive force (level 0) is formed on the metal surface, and the neutral salt mist resistance of the protective coating exceeds 2000 hours and is improved by 140% or above compared with that of a traditional coating. Meanwhile, the coating has an efficient self-repairing function (the repairing efficiency is larger than or equal to 88%) through the unique microencapsulation technology, when the coating is damaged, a corrosion inhibitor can be automatically released to form a protection film, the protection service life is remarkably prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of film-forming material preparation technology, and in particular to a self-healing hard film anti-corrosion film-forming material for non-rotating parts and its preparation method. Background Technology

[0002] In fields such as power equipment, marine engineering, and chemical equipment, non-rotating metal components are exposed to corrosive environments such as humidity, salt spray, and chemical media for extended periods, facing severe corrosion problems. Traditional anti-corrosion coatings, such as epoxy resins and polyurethane coatings, suffer from low hardness, insufficient corrosion resistance, and short service life. Especially when the coating suffers mechanical damage, corrosive media can rapidly penetrate the base metal, leading to corrosion propagation beneath the coating and significantly shortening the protective lifespan.

[0003] While some self-healing coatings have emerged in existing technologies, most suffer from low repair efficiency, limited repair cycles, and difficulty in balancing mechanical and corrosion-resistant properties. For example, some microcapsule-based self-healing systems often sacrifice the coating's mechanical strength; while some inorganic zinc-rich coatings, although possessing high hardness, lack self-healing capabilities and exhibit poor flexibility. Furthermore, existing hard anti-corrosion coatings are prone to brittle cracking and decreased adhesion during long-term use, making it difficult to meet the long-term protection requirements of harsh industrial environments. Summary of the Invention

[0005] The purpose of this invention is to provide an oil-soluble corrosion inhibitor and its corrosion inhibition evaluation method, which aims to solve the problems of brittle cracking and decreased adhesion that traditional hard anti-corrosion coatings are prone to during long-term use.

[0006] In a first aspect, the present invention provides a self-healing hard film anti-corrosion film-forming material for non-rotating parts, comprising the following raw materials in parts by weight: 25-40 parts of modified nano-silica, 30-50 parts of fluorinated polyurethane prepolymer, 5-10 parts of microencapsulated corrosion inhibitor, 0.5-3 parts of graphene nanosheets, and 25-35 parts of a mixed solvent of propylene glycol methyl ether acetate and isophorone.

[0007] In some embodiments, the modified nano-silica has a particle size of 50-80 nm, the fluorine content of the fluorinated polyurethane prepolymer is ≥18%, and the mass ratio of propylene glycol methyl ether acetate to isophorone is 2.5-3.5:1.

[0008] Secondly, the present invention provides a method for preparing a self-healing hard film anti-corrosion film-forming material for non-rotating parts, the preparation method comprising: Step S01: Add 25-40 parts of nano-silica with a particle size of 50-80nm to a 5% ethanol solution, disperse by ultrasonication, add 3% silane coupling agent KH-550 (by mass of silica) dropwise, stir at 80℃ for 4h, filter, dry at 120℃ for 2h to obtain modified nano-silica with surface grafted organic groups. Step S02: Under nitrogen protection, 15-20 parts of hexafluoropropylene dimer and 25-30 parts of toluene diisocyanate are reacted at 80°C for 3 hours to generate fluorinated isocyanate intermediate. Step S03: Add 30-35 parts of polytetrahydrofuran ether diol with a molecular weight of 2000 and 5-8 parts of 1,4-butanediol. After chain extension at 75°C for 2 hours, end-cap with 3-5 parts of diethanolamine to obtain a fluorinated polyurethane prepolymer with a fluorine content ≥18%. Step S04: Dissolve 10 parts of 8-hydroxyquinoline in 30 parts of methyl methacrylate, add 0.5 parts of sodium dodecyl sulfate as an emulsifier to form a core solution, prepolymerize 15 parts of urea and 20 parts of formaldehyde at pH=4.5, and polymerize them with the core solution at 50℃ for 4 hours. After centrifugation and washing with ethanol, microcapsules with a particle size of 2-5 μm and a corrosion inhibitor loading of 72% are obtained. Step S05: Add 0.5-3 parts of graphene nanosheets with ≤3 layers to 15-20 parts of propylene glycol methyl ether acetate, shear at 10000 rpm for 15 min, and then sonicate to obtain a graphene dispersion. Step S06: Mix modified nano-silica, fluorinated polyurethane prepolymer, microencapsulated corrosion inhibitor, and graphene dispersion, add 10-15 parts of isophorone, adjust the mass ratio of propylene glycol methyl ether acetate to isophorone to 2.5-3.5:1, control the viscosity to 800-1200 mPa·s, and form a 20-50 μm coating on the surface of non-rotating parts by electrostatic spraying (voltage 60kV, distance 15cm). After curing at 80℃ for 1h, cool at room temperature to obtain a self-healing hard film anti-corrosion film-forming material.

[0009] In some embodiments, the ultrasonic dispersion frequency in step S01 is 40 kHz and the dispersion time is 30 min.

[0010] In some embodiments, the flow rate of nitrogen protection in step S02 is 0.5-1 L / min.

[0011] In some embodiments, the stirring speed for interfacial polymerization in step S04 is 300-500 rpm.

[0012] In some embodiments, the ultrasonic treatment power in step S05 is 800W and the treatment time is 60min.

[0013] In some embodiments, the stirring speed in step S06 is 800-1000 rpm, and the stirring time is 2 hours.

[0014] In some embodiments, the coating has a pencil hardness ≥2H, an adhesion grade of 0, and a neutral salt spray resistance ≥2000h.

[0015] Compared with the prior art, the present invention has the following advantages: 1. Through the synergistic effect of modified nano-silica and fluorinated polyurethane, the coating achieves both high hardness (≥2H) and good adhesion (Grade 0). Nano-silica provides a rigid framework, while fluorinated polyurethane imparts flexibility and density to the coating. The combination of the two enables the coating to maintain hardness while exhibiting good stress dispersion capabilities, achieving a neutral salt spray resistance of over 2000 hours.

[0016] 2. The self-healing hard-film anti-corrosion film-forming material prepared by this invention contains microencapsulated corrosion inhibitors that automatically release 8-hydroxyquinoline corrosion inhibitors when the coating is damaged, forming a protective film at the damaged site and effectively inhibiting corrosion propagation. The microcapsule particle size is 2-5 μm, and the corrosion inhibitor loading reaches 72%, ensuring repair efficiency and capacity. Synergistically acting with graphene nanosheets, it forms a multi-dimensional protective network, enhancing the repair effect.

[0017] 3. The self-healing hard-film anti-corrosion film-forming material prepared by this invention, a fluorinated polyurethane prepolymer (fluorine content ≥18%), provides excellent weather resistance, chemical resistance, and anti-aging properties. The addition of graphene nanosheets enhances the barrier properties and mechanical strength of the coating, while also improving its thermal and electrical conductivity, which helps prevent electrochemical corrosion.

[0018] 4. By using a specific solvent ratio (propylene glycol methyl ether acetate to isophorone mass ratio 2.5-3.5:1) and viscosity control (800-1200 mPa·s), the material has good leveling and atomization properties, making it suitable for electrostatic spraying and capable of forming a uniform and dense 20-50 μm coating. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects.

[0021] Example 1 (1) Formulation: Modified nano silica (60nm): 32 parts, fluorinated polyurethane prepolymer (fluorine content 20%): 40 parts, microencapsulated corrosion inhibitor (particle size 3μm, loading 72%): 7 parts, graphene nanosheets (2 layers): 1.5 parts, propylene glycol methyl ether acetate: 22 parts, isophorone: 8 parts.

[0022] (2) Preparation process: Step S01: Add 32 parts of 60nm nano-silica to a 5% ethanol solution, disperse by ultrasonication at 40kHz for 30min, then add 0.96 parts of silane coupling agent KH-550, stir and react at 80℃ for 4h, filter, and dry at 120℃ for 2h to obtain modified nano-silica. Step S02: Under nitrogen protection (flow rate 0.8 L / min), 18 parts of hexafluoropropylene dimer and 28 parts of toluene diisocyanate were reacted at 80 °C for 3 h to generate fluorinated isocyanate intermediate; Step S03: Add 32 parts of polytetrahydrofuran ether diol and 6 parts of 1,4-butanediol, extend the chain at 75°C for 2 hours, and then end-cap with 4 parts of diethanolamine to obtain a fluorinated polyurethane prepolymer with a fluorine content of 20%. Step S04: Dissolve 10 parts of 8-hydroxyquinoline in 30 parts of methyl methacrylate, add 0.5 parts of sodium dodecyl sulfate to form a core solution, prepolymerize 15 parts of urea and 20 parts of formaldehyde at pH=4.5, and polymerize with the core solution at 50℃ for 4h (stirring speed 400rpm). After centrifugation and washing with ethanol, obtain microcapsules with a particle size of 3μm. Step S05: Add 1.5 parts of graphene nanosheets to 18 parts of propylene glycol methyl ether acetate, shear at 10000 rpm for 15 min, and then sonicate at 800W for 60 min to obtain a graphene dispersion. Step S06: Mix modified nano-silica, fluorinated polyurethane prepolymer, microencapsulated corrosion inhibitor, and graphene dispersion, add 8 parts of isophorone dropwise, stir at 900 rpm for 2 hours, control the viscosity to 1000 mPa·s, form a 30 μm coating by electrostatic spraying (voltage 60 kV, distance 15 cm), and cure at 80℃ for 1 hour.

[0023] (III) Performance results of the self-healing hard film anti-corrosion film-forming material prepared in Example 1 Pencil hardness (according to GB / T 6739-2006): 3H; Adhesion (according to GB / T 9286-1998 cross-cut test): Grade 0; Resistance to neutral salt spray (according to GB / T 1771-2007): 2400h; Self-healing efficiency (microscopic observation 24 hours after artificial scratch): 92%; Flexibility (according to GB / T 1731-1993): 1mm; Impact resistance (according to GB / T1732-1993): 50kg·cm.

[0024] Example 2 This embodiment is basically the same as Embodiment 1, except that the formula is adjusted as follows: modified nano silica (50nm): 40 parts, fluorinated polyurethane prepolymer (fluorine content 22%): 50 parts, microencapsulated corrosion inhibitor (particle size 2μm): 5 parts, graphene nanosheets (1 layer): 3 parts, propylene glycol methyl ether acetate: 24 parts, isophorone: 7 parts.

[0025] Performance results: Pencil hardness: 4H; Adhesion: Grade 0; Neutral salt spray resistance: 2200h; Self-healing efficiency: 88%; Flexibility: 2mm; Impact resistance: 45kg·cm.

[0026] Example 3 This embodiment is basically the same as Embodiment 1, except that the formula is adjusted as follows: modified nano silica (80nm): 25 parts, fluorinated polyurethane prepolymer (fluorine content 18%): 30 parts, microencapsulated corrosion inhibitor (particle size 5μm): 10 parts, graphene nanosheets (3 layers): 0.5 parts, propylene glycol methyl ether acetate: 19 parts, isophorone: 6 parts.

[0027] Performance results: Pencil hardness: 2H, adhesion: grade 0, resistance to neutral salt spray: 2600h, self-healing efficiency: 96%, flexibility: 1mm, impact resistance: 55kg·cm.

[0028] Comparative Example 1 (1) Formulation: Fluorinated polyurethane prepolymer: 72 parts, other components are the same as in Example 1.

[0029] (2) Preparation process: Step S01 is omitted, and the rest is the same as in Example 1.

[0030] (3) Performance results: Pencil hardness: H, adhesion: Grade 1, resistance to neutral salt spray: 800h, self-healing efficiency: 90%, flexibility: 1mm, impact resistance: 40kg·cm.

[0031] Comparative Example 2 (1) Formulation: Add 7 parts of 8-hydroxyquinoline directly, and the other components are the same as in Example 1.

[0032] (2) Preparation process: Step S04 is omitted, and the rest is the same as in Example 1.

[0033] (3) Performance results: Pencil hardness: 3H, adhesion: grade 0, resistance to neutral salt spray: 1200h, self-healing efficiency: 0%, flexibility: 1mm, impact resistance: 50kg·cm.

[0034] Comparative Example 3 (1) Formulation: Remove graphene nanosheets, other components are the same as in Example 1.

[0035] (2) Preparation process: Step S05 is omitted, and the rest is the same as in Example 1.

[0036] (3) Performance results: Pencil hardness: 2H, adhesion: grade 0, resistance to neutral salt spray: 1800h, self-healing efficiency: 91%, flexibility: 2mm, impact resistance: 35kg·cm.

[0037] Comparative Example 4 Epoxy zinc-rich coatings sold on the market.

[0038] Performance results: Pencil hardness: 2H, Adhesion: Grade 1, Neutral salt spray resistance: 1000h, Self-healing efficiency: 0%, Flexibility: 3mm, Impact resistance: 30kg·cm.

[0039] In summary, the data above shows that Examples 1-3 exhibit excellent overall performance, demonstrating a good synergistic effect among the components under specific ratios. Comparative Example 1 (without nano-silica) showed a significant decrease in hardness and adhesion, while Comparative Example 2 (without microcapsules) completely lost its self-healing function. Example 2 achieved the highest hardness (4H) by increasing the nano-silica content, and Example 3 achieved the best self-healing efficiency (96%) by increasing the microcapsule content. Furthermore, compared to Comparative Example 4, Example 1 showed a 140% improvement in salt spray resistance, an improvement in adhesion from level 1 to level 0, and a 67% improvement in impact resistance.

[0040] It should be noted that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The directional terms "inner" and "outer" refer to the inside or outside relative to the outline of each component itself. A device "above other devices or structures" or "on top of other devices or structures" will be subsequently positioned "below other devices or structures" or "under other devices or structures." Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0041] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0042] It should also be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this application refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0043] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0044] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the description of this application, or any direct or indirect application in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A self-healing hard film anti-corrosion film-forming material for non-rotating parts, characterized in that, It is composed of the following raw materials in parts by weight: 25-40 parts modified nano silica, 30-50 parts fluorinated polyurethane prepolymer, 5-10 parts microencapsulated corrosion inhibitor, 0.5-3 parts graphene nanosheets, and 25-35 parts mixed solvent of propylene glycol methyl ether acetate and isophorone.

2. The self-healing hard film anti-corrosion film-forming material for non-rotating parts according to claim 1, characterized in that, The modified nano-silica has a particle size of 50-80 nm, the fluorine content of the fluorinated polyurethane prepolymer is ≥18%, and the mass ratio of propylene glycol methyl ether acetate to isophorone is 2.5-3.5:

1.

3. A method for preparing a self-healing hard film anti-corrosion film-forming material for non-rotating parts according to any one of claims 1-2, characterized in that, The preparation method includes: Step S01: Add 25-40 parts of nano-silica with a particle size of 50-80nm to a 5% ethanol solution, disperse by ultrasonication, add 3% silane coupling agent KH-550 (by mass of silica) dropwise, stir at 80℃ for 4h, filter, dry at 120℃ for 2h to obtain modified nano-silica with surface grafted organic groups. Step S02: Under nitrogen protection, 15-20 parts of hexafluoropropylene dimer and 25-30 parts of toluene diisocyanate are reacted at 80°C for 3 hours to generate fluorinated isocyanate intermediate. Step S03: Add 30-35 parts of polytetrahydrofuran ether diol with a molecular weight of 2000 and 5-8 parts of 1,4-butanediol. After chain extension at 75°C for 2 hours, end-cap with 3-5 parts of diethanolamine to obtain a fluorinated polyurethane prepolymer with a fluorine content ≥18%. Step S04: Dissolve 10 parts of 8-hydroxyquinoline in 30 parts of methyl methacrylate, add 0.5 parts of sodium dodecyl sulfate as an emulsifier to form a core solution, prepolymerize 15 parts of urea and 20 parts of formaldehyde at pH=4.5, and polymerize them with the core solution at 50℃ for 4 hours. After centrifugation and washing with ethanol, microcapsules with a particle size of 2-5 μm and a corrosion inhibitor loading of 72% are obtained. Step S05: Add 0.5-3 parts of graphene nanosheets with ≤3 layers to 15-20 parts of propylene glycol methyl ether acetate, shear at 10000 rpm for 15 min, and then sonicate to obtain a graphene dispersion. Step S06: Mix modified nano-silica, fluorinated polyurethane prepolymer, microencapsulated corrosion inhibitor, and graphene dispersion, add 10-15 parts of isophorone, adjust the mass ratio of propylene glycol methyl ether acetate to isophorone to 2.5-3.5:1, control the viscosity to 800-1200 mPa·s, and form a 20-50 μm coating on the surface of non-rotating parts by electrostatic spraying (voltage 60kV, distance 15cm). After curing at 80℃ for 1h, cool at room temperature to obtain a self-healing hard film anti-corrosion film-forming material.

4. The method for preparing the self-healing hard film anti-corrosion film-forming material for non-rotating parts according to claim 3, characterized in that, In step S01, the ultrasonic dispersion frequency is 40kHz and the dispersion time is 30min.

5. The method for preparing a self-healing hard film anti-corrosion film-forming material for non-rotating parts according to claim 3, characterized in that, The flow rate of nitrogen protection in step S02 is 0.5-1 L / min.

6. The method for preparing the self-healing hard film anti-corrosion film-forming material for non-rotating parts according to claim 3, characterized in that, The stirring speed for interfacial polymerization in step S04 is 300-500 rpm.

7. The method for preparing a self-healing hard film anti-corrosion film-forming material for non-rotating parts according to claim 3, characterized in that, In step S05, the ultrasonic treatment power is 800W and the treatment time is 60min.

8. The method for preparing the self-healing hard film anti-corrosion film-forming material for non-rotating parts according to claim 3, characterized in that, The mixing speed in step S06 is 800-1000 rpm, and the mixing time is 2 hours.

9. The method for preparing a self-healing hard film anti-corrosion film-forming material for non-rotating parts according to claim 3, characterized in that, The coating has a pencil hardness ≥2H, adhesion grade 0, and neutral salt spray resistance ≥2000h.