Fluorocarbon-modified cured metallic paint and method for preparing the same

Abstract

The present application relates to a kind of fluorocarbon modified solidified metal paint and its preparation method, belong to coating technical field, fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin four modified resin in paint is by trifluorochloroethylene, 4-hydroxybutyl vinyl ether, gamma-methacryloyloxypropyl trimethoxysilane, perfluoro-n-propyl vinyl ether, tert-butyl peroxypivalate, hydrogenated rosin glyceride, organic bismuth catalyst and hydroquinone polymerization inhibitor etc. It is obtained.Nano-silicon dioxide-fluoroalkyl phosphate-perfluoropolyether composite dispersion in paint is by butyl acetate, dispersing agent, fumed silica, perfluorooctyl phosphate, perfluoropolyether alcohol, KH-550 silane coupling agent is obtained.Hindered amine-titanium composite curing accelerator in paint component is by isopropyl alcohol, tetraisopropyl titanate, acetylacetone and hindered amine light stabilizer is obtained.Each component is compounded with other functional components, so that the paint film realizes high weather resistance, high chemical corrosion resistance, self-cleaning, wide temperature range film-forming property.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a fluorocarbon modified curing metallic paint and its preparation method. Background Technology

[0002] Metallic paint is a core coating product for the protection of industrial and building metal substrates, widely used in steel structures, machinery, aluminum alloy doors and windows, pipes, vehicles, and outdoor metal components. Currently, mainstream metallic paints use acrylic, epoxy resin, and polyurethane as the main film-forming substances, combined with curing agents to achieve cross-linking and curing at room temperature or with heating. The paint film's shielding effect and adhesion provide rust prevention, decoration, and basic protection. As the application scenarios for metal products continue to expand, metallic paint has evolved from a single protective function to a comprehensive approach encompassing high weather resistance, high gloss, high hardness, and ease of application, becoming a key material for improving the service life and appearance quality of metal products.

[0003] Despite the widespread application of existing cured metallic paints, some performance shortcomings remain under harsh environments and high-end demands. Firstly, their weather resistance and durability are insufficient. Ordinary acrylic and polyurethane metallic paints, when exposed to UV radiation, rain, and high / low temperature cycles for extended periods, are prone to loss of gloss, fading, chalking, and cracking, resulting in rapid film aging and failing to meet the requirements for long-term outdoor use. Secondly, their chemical and stain resistance is poor. The high surface energy of the paint film makes it prone to attracting dust and oil, making cleaning difficult. When exposed to corrosive media such as acids, alkalis, and solvents, they are prone to swelling, discoloration, and decreased adhesion, leading to a rapid decline in protective effectiveness. Furthermore, some systems require stringent curing conditions; incomplete film formation under low temperature or high humidity environments affects the final coating quality. Therefore, continuous improvement of metallic paint systems is needed to enhance weather resistance, durability, chemical resistance, stain resistance, and high / low temperature moldability to meet the long-term protection requirements under harsh environments. Summary of the Invention

[0004] The weather resistance, durability, chemical resistance, stain resistance, and high / low temperature molding properties of existing metallic paints need improvement. This invention provides a fluorocarbon-modified curing metallic paint and its preparation method. The method involves preparing a fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin, a nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, a hindered amine-titanium composite curing accelerator, and other components in a reasonable ratio. The resulting paint film possesses both rigidity and toughness, strong dielectric shielding ability, and extremely low surface energy, enabling long-term protection and decoration in harsh environments such as steel structures, mechanical equipment, and outdoor metal components, significantly extending the service life of metal products. The specific technical solution is as follows:

[0005] A fluorocarbon-modified curable metallic paint is prepared by mixing paint components and curing agent components at a mass ratio of 100:18-22, and adjusting the viscosity with a mixed solvent. The paint components include the following raw materials in parts by mass: 50-53 parts of fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin, 12-14 parts of hydroxyl acrylic resin, 16-20 parts of rutile titanium dioxide, 3-5 parts of zinc phosphate, 6-8 parts of barium sulfate, 20-25 parts of nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, 0.5-0.8 parts of hindered amine-titanium composite curing accelerator, 0.3-0.6 parts of leveling agent, 0.4-0.7 parts of dispersant, 0.2-0.4 parts of defoamer, 0.8-1.2 parts of ultraviolet absorber, and 10-12 parts of mixed solvent. The curing agent component is a blocked isocyanate curing agent.

[0006] In the above-mentioned metallic paint, the viscosity of the mixed solvent is adjusted to 20-30 seconds of Forecast cup viscosity; the mixed solvent is butyl acetate to propylene glycol methyl ether acetate in a mass ratio of 1:0.8-1; the leveling agent is BYK-320, BYK-306 or BYK-333; the dispersant is BYK-163; the defoamer is BYK-066N; and the ultraviolet absorber is UV-531.

[0007] In the aforementioned metallic paint, the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin is prepared by mixing trifluorochloroethylene, 4-hydroxybutyl vinyl ether, γ-methacryloyloxypropyltrimethoxysilane, perfluoropropyl vinyl ether, tert-butyl peroxypentanoate, mixed solvent, hydrogenated rosin glycerol ester, organic bismuth catalyst, and hydroquinone polymerization inhibitor in a mass ratio of (23-24):(19-21):(3-5):(4-6):(0.7-0.9):(50-55):(4-6):(0.1-0.2):(0.05-0.1). The hindered amine-titanium composite curing accelerator is prepared by isopropanol, tetraisopropyl titanate, acetylacetone, and hindered amine light stabilizer in a mass ratio of (65-70):(15-18):(8-10):(6-8). The nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion is prepared by butyl acetate, dispersant, fumed silica, perfluorooctyl phosphate, perfluoropolyether alcohol, and KH-550 silane coupling agent in a mass ratio of (70-80):(0.5-0.8):(8-10):(10-12):(8-10):(1-1.5).

[0008] Furthermore, the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin comprises trifluorochloroethylene, 4-hydroxybutyl vinyl ether, γ-methacryloyloxypropyltrimethoxysilane, perfluoropropyl vinyl ether, tert-butyl peroxypentanoate, mixed solvent, hydrogenated rosin glycerol ester, organic bismuth catalyst, and hydroquinone polymerization inhibitor in the following proportions: (23-24): (19-21): (3-5): (4-6): (0.7-0.9): (50-55) The mass ratio of trifluorochloroethylene, 4-hydroxybutyl vinyl ether, γ-methacryloyloxypropyltrimethoxysilane, perfluoropropyl vinyl ether, and tert-butyl peroxypentanoate was first added to a mixed solvent and stirred at 100-105°C for 3-4 hours. Hydrogenated rosin glycerol ester and organic bismuth catalyst were added at 85-90°C and stirred for 3-4 hours. Hydroquinone polymerization inhibitor was added below 50°C and stirred to obtain the final product.

[0009] Furthermore, the preparation method of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin includes the following steps: by weight, 23-24 parts of trifluorochloroethylene, 19-21 parts of 4-hydroxybutyl vinyl ether, 3-5 parts of γ-methacryloyloxypropyltrimethoxysilane, 4-6 parts of perfluoro-n-propyl vinyl ether, and 0.7-0.9 parts of tert-butyl peroxypentanoate are added to 50-55 parts of butyl acetate and propylene glycol methyl ether. In a mixed solvent with an acetate mass ratio of 1:0.8-1, the mixture is stirred at 100-105°C for 3-4 hours, then cooled to 85-90°C. 4-6 parts of hydrogenated rosin glycerol ester and 0.1-0.2 parts of organic bismuth catalyst are added, and the mixture is stirred for 3-4 hours. The temperature is then lowered to below 50°C, and 0.05-0.1 parts of hydroquinone polymerization inhibitor are added. The mixture is stirred for 10-15 minutes and filtered to obtain a fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin.

[0010] Furthermore, the hindered amine-titanium composite curing accelerator is prepared by stirring isopropanol, tetraisopropyl titanate, acetylacetone, and hindered amine light stabilizer in a mass ratio of (65-70):(15-18):(8-10):(6-8).

[0011] Furthermore, the preparation method of the hindered amine-titanium composite curing accelerator includes the following steps: 65-70 parts by weight of isopropanol and 15-18 parts by weight of tetraisopropyl titanate are mixed, 8-10 parts by weight of acetylacetone are added dropwise, the mixture is stirred at 50-55°C for 2-3 hours, 6-8 parts by weight of hindered amine light stabilizer are added at 60-65°C and stirred for 1-1.5 hours, and then filtered to obtain the hindered amine-titanium composite curing accelerator.

[0012] Furthermore, the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion is prepared by mixing butyl acetate, dispersant, fumed silica, perfluorooctyl phosphate, perfluoropolyether alcohol, and KH-550 silane coupling agent in a mass ratio of (70-80):(0.5-0.8):(8-10):(10-12):(8-10):(1-1.5). After stirring butyl acetate and dispersant, fumed silica is added and stirred for dispersion. Perfluorooctyl phosphate and perfluoropolyether alcohol are added and stirred at 50-55°C. KH-550 silane coupling agent is added below 40°C and stirred. The mixture is then milled to a fineness of less than 10 μm.

[0013] Furthermore, the preparation method of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion includes the following steps: by weight, 85-90 parts of butyl acetate and 0.5-0.8 parts of dispersant are stirred, and 8-10 parts of fumed silica are added and stirred to disperse; 3-4 parts of perfluorooctyl phosphate and 1-2 parts of perfluoropolyether alcohol are added, and stirred at 50-55°C for 1-1.5 hours; 1-1.5 parts of KH-550 silane coupling agent are added below 40°C and stirred, and the mixture is milled to a fineness of less than 10 μm, filtered, and the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion is obtained.

[0014] The preparation method of the above-mentioned fluorocarbon modified curable metallic paint includes the following steps: S1: According to the paint composition formula, mix the solvent, dispersant, and defoamer, add rutile titanium dioxide, zinc phosphate, and barium sulfate for shear dispersion, and mill to a fineness of less than 15μm; add fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin and hydroxyl acrylic resin while stirring, add nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, leveling agent, ultraviolet absorber, and hindered amine-titanium composite curing accelerator while stirring to obtain the paint composition; S2: When using, mix the paint components and hardener components according to the mass ratio, adjust the viscosity with the mixed solvent to the Ford cup viscosity of 20-30 seconds, let stand, and you will get the metallic paint.

[0015] The present invention provides a fluorocarbon-modified curable metallic paint and its preparation method, which have the following beneficial effects: I. The fluorocarbon modified curing metallic paint of this invention achieves multiple synergistic properties such as high adhesion, high hardness, high weather resistance, high chemical corrosion resistance, self-cleaning, and wide temperature range film formation through the construction of an organic-inorganic hybrid crosslinking network. It solves the core pain points of traditional metallic paints, such as poor weather resistance, low stain resistance, and incomplete film formation at low temperature and high humidity. The paint film has both rigidity and toughness, strong medium shielding ability, and extremely low surface energy. It can achieve long-term protection and decoration in harsh scenarios such as steel structures, mechanical equipment, and outdoor metal components, and significantly improve the service life of metal products.

[0016] II. In the preparation of the quaternary modified resin of fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin, trifluorochloroethylene and perfluoropropyl vinyl ether impart extremely low surface energy and high chemical bond energy to the coating film, achieving weather resistance, chemical resistance, and self-cleaning properties. γ-methacryloyloxypropyltrimethoxysilane hydrolyzes and condenses to form a Si-O-Si inorganic rigid network, improving crosslinking density, hardness, and substrate adhesion. 4-hydroxybutyl vinyl ether provides hydroxyl functional groups, ensuring reaction sites for crosslinking and curing. Hydrogenated rosin glycerol ester introduces a fused-ring rigid structure and polar ester groups, enhancing the substrate's wetting and anchoring ability and improving internal stress distribution. Copolymerization at 100–105℃ forms the basic resin skeleton, hydrogenated rosin modification at 85–90℃ achieves polar anchoring and toughening, and the addition of polymerization inhibitors below 50℃ prevents resin self-polymerization. Precise control of dosage and parameters ensures the integrity of the resin structure and the activity of functional groups, ensuring the crosslinking efficiency of the resin and curing agent.

[0017] III. In the preparation of the hindered amine-titanium composite curing accelerator, tetraisopropyl titanate serves as a crosslinking catalyst, reducing the crosslinking activation energy between hydroxyl groups and isocyanates; acetylacetone chelates and stabilizes the titanate, preventing premature hydrolysis and aggregation; the hindered amine light stabilizer is composited with the titanium center, achieving in-situ free radical capture and peroxide decomposition; isopropanol serves as a dispersion medium, ensuring uniform dispersion of all components. A stable titanium chelate is formed through a chelation reaction at 50–55℃, and the hindered amine light stabilizer is introduced at 60–65℃ to achieve composite formation. Temperature control prevents chelate decomposition and light stabilizer deactivation, ensuring the synergistic effect of both curing catalysis and light stabilization.

[0018] IV. In the preparation of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, fumed silica, as rigid particles, enhances the hardness and scratch resistance of the paint film; fluoroalkyl phosphate anchors the nanoparticles and resin with polar phosphate groups, and the directional arrangement of fluoroalkyl groups reduces surface energy; perfluoropolyether alcohol lubricates and reduces viscosity, improving the compatibility between the fluorinated component and the resin; KH-550 silane coupling agent achieves chemical bonding between inorganic nanoparticles and organic resin, eliminating interfacial defects. High-speed shear dispersion ensures the dispersibility of nano-silica, 50-55℃ achieves the bonding of the fluorinated component and nanoparticles, and sand milling to a fineness of less than 10μm avoids particle defects in the paint film. Control of particle size and dispersion ensures that nanoparticles are uniformly distributed in the paint film, exerting a synergistic reinforcing effect.

[0019] V. In the mixing and preparation steps of metallic paint, the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin and hydroxyl acrylic resin are added after grinding to avoid damage to the resin molecular chains by high-speed shearing and to ensure the crosslinking activity of the resin. The blending of the two resins achieves the basic construction of an organic-inorganic hybrid network. Finally, the composite dispersion, leveling agent, UV absorber, and curing accelerator are added. The functional additives are added later to avoid their loss during the sanding process; the leveling agent improves the leveling properties of the paint film during application and avoids surface defects such as pinholes and orange peel; the UV absorber and the hindered amine light stabilizer in the curing accelerator form a synergistic light stabilizing system to improve weather resistance.

[0020] In summary, the fluorocarbon, perfluoropolyether, and hydrogenated rosin quaternary modified resin forms a covalently bonded organic-inorganic hybrid network with the inorganic siloxane segments, balancing the rigidity and toughness of the paint film and resolving the contradiction of traditional coatings being hard and brittle, or tough and soft. The hindered amine-titanium composite curing accelerator lowers the crosslinking activation energy, ensuring complete crosslinking at room temperature, during baking, and under low temperature and high humidity conditions. It precisely matches the hydroxyl functional groups of the fluorocarbon, perfluoropolyether, and hydrogenated rosin quaternary modified resin, increasing the crosslinking density of the paint film. The leveling agent and the surface tension-reducing effect of the composite dispersion match the volume shrinkage during the curing process, preventing internal stress cracking of the paint film and improving film quality. The fluorocarbon, perfluoropolyether, and fluoroalkyl phosphate and perfluoropolyether alcohol components of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin form a low surface energy layer on the paint film surface. The micro-rough structure constructed by nano-silica synergistically achieves a lotus leaf effect with the low surface energy layer, improving hydrophobicity and stain resistance, and realizing self-cleaning function. The UV absorber absorbs ultraviolet light, and the hindered amine light stabilizer in the hindered amine-titanium composite curing accelerator captures free radicals generated by photoaging in situ and decomposes peroxides. The high chemical bond energy of the fluorocarbon segments resists UV degradation. The three components form a triple weather-resistant protection system of UV absorption, free radical scavenging, and molecular chain stabilization, delaying the aging of the paint film. The polar ester groups and siloxane segments of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin form hydrogen bonds and covalent bonds with the metal substrate. The KH-550 silane coupling agent of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion further strengthens the interface bonding between inorganic-organic-substrate. Zinc phosphate forms a passivation film with the metal substrate. The three work synergistically to improve the adhesion between the paint film and the substrate, ensuring that the coating does not peel off. Detailed Implementation

[0021] Some embodiments are given below, but the present invention is not limited to these embodiments.

[0022] Example 1 A fluorocarbon-modified curable metallic paint is prepared by mixing paint components and curing agent components at a mass ratio of 100:20 and adjusting the viscosity with a mixed solvent. The paint components include the following raw materials in parts by mass: 52 parts of fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin, 13 parts of hydroxyl acrylic resin, 18 parts of rutile titanium dioxide, 4 parts of zinc phosphate, 7 parts of barium sulfate, 23 parts of nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, 0.6 parts of hindered amine-titanium composite curing accelerator, 0.5 parts of leveling agent, 0.6 parts of dispersant, 0.3 parts of defoamer, 1 part of ultraviolet absorber, and 11 parts of mixed solvent. The curing agent component is a blocked isocyanate curing agent. The mixed solvent is butyl acetate to propylene glycol methyl ether acetate in a mass ratio of 1:0.9; the leveling agent is BYK-320; the dispersant is BYK-163; the defoamer is BYK-066N; and the ultraviolet absorber is UV-531.

[0023] The preparation method of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin includes the following steps: Under nitrogen protection, in a reactor equipped with a high-efficiency reflux condenser and a pressure balancing device, 23.5 parts by mass of trifluorochloroethylene, 20 parts by mass of 4-hydroxybutyl vinyl ether, 4 parts by mass of γ-methacryloyloxypropyltrimethoxysilane, 5 parts by mass of perfluoro-n-propyl vinyl ether, and 0.8 parts by mass of tert-butyl peroxypentanoate are added to a mixed solvent of 52 parts by mass of butyl acetate and propylene glycol methyl ether acetate in a mass ratio of 1:0.9. The mixture is stirred at 450 rpm for 3.5 h at a temperature range of 100–105 °C. The temperature is then lowered to 85–90 °C, and 5 parts by mass of hydrogenated rosin glycerol ester and 0.15 parts by mass of organic bismuth catalyst are added. The mixture is stirred at 450 rpm for 3.5 h (the reaction is maintained at this temperature until the acid value is <5 mg). KOH / g); cool to 45℃, add 0.08 parts hydroquinone polymerization inhibitor, stir at 450 rpm for 12 min, filter through a 200-mesh filter to obtain fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin.

[0024] The preparation method of the hindered amine-titanium composite curing accelerator includes the following steps: by mass, 68 parts of isopropanol are added to 16 parts of tetraisopropyl titanate under stirring at 220 rpm and mixed evenly. 9 parts of acetylacetone are added dropwise, the temperature is raised to 50-55℃, and the mixture is stirred at 450 rpm for 2.5 h. The temperature is then raised to 60-65℃, 7 parts of hindered amine light stabilizer are added, and the mixture is stirred for another 1 h. The mixture is cooled to room temperature and filtered through a 150-mesh filter to obtain the hindered amine-titanium composite curing accelerator.

[0025] The preparation method of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion includes the following steps: 75 parts by mass of butyl acetate and 0.65 parts by mass of dispersant (BYK-163) are stirred at 700 rpm for 12 min, 9 parts by mass of fumed silica are added, and the mixture is dispersed by shearing and stirring at 2200 rpm for 50 min; 11 parts by mass of perfluorooctyl phosphate and 9 parts by mass of perfluoropolyether alcohol are added, and the mixture is stirred at 1100 rpm for 1 h at a temperature range of 50-55℃; the temperature is lowered to 35℃, 1.2 parts by mass of KH-550 silane coupling agent are added, and the mixture is stirred for another 35 min, then allowed to stand to defoam; the mixture is transferred to a sand mill (zirconium bead media) and milled to a fineness of less than 10 μm, then filtered through a 200-mesh filter to obtain the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion.

[0026] The preparation method of the above-mentioned fluorocarbon modified curable metallic paint includes the following steps: S1: According to the paint composition formula, the mixed solvent, dispersant, and defoamer are stirred at 550 rpm for 12 min; rutile titanium dioxide, zinc phosphate, and barium sulfate are added and sheared and dispersed at 1800 rpm for 35 min, then transferred to a sand mill and sand-milled to a fineness of less than 15 μm; transferred to a paint mixing tank, and fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin and hydroxyl acrylic resin are added under stirring at 700 rpm, and stirring is continued for 18 min; nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, leveling agent, ultraviolet absorber, hindered amine-titanium composite curing accelerator are added, and stirring is continued at 550 rpm for 18 min to obtain the paint composition; S2: When using, mix the paint components and hardener components according to the mass ratio, adjust the viscosity to the application viscosity with the mixed solvent, and let stand for 8 minutes to obtain metallic paint.

[0027] Example 2 A fluorocarbon-modified curable metallic paint is prepared by mixing paint components and curing agent components at a mass ratio of 100:18 and adjusting the viscosity with a mixed solvent. The paint components include the following raw materials in parts by mass: 50 parts of fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin, 12 parts of hydroxyl acrylic resin, 16 parts of rutile titanium dioxide, 3 parts of zinc phosphate, 6 parts of barium sulfate, 20 parts of nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, 0.5 parts of hindered amine-titanium composite curing accelerator, 0.3 parts of leveling agent, 0.4 parts of dispersant, 0.2 parts of defoamer, 0.8 parts of ultraviolet absorber, and 10 parts of mixed solvent. The curing agent component is a blocked isocyanate curing agent. The mixed solvent is butyl acetate to propylene glycol methyl ether acetate in a mass ratio of 1:0.8; the leveling agent is BYK-306; the dispersant is BYK-163; the defoamer is BYK-066N; and the ultraviolet absorber is UV-531.

[0028] The preparation method of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin includes the following steps: Under nitrogen protection, in a reactor equipped with a high-efficiency reflux condenser and a pressure balancing device, 24 parts by mass of trifluorochloroethylene, 21 parts by mass of 4-hydroxybutyl vinyl ether, 5 parts by mass of γ-methacryloyloxypropyltrimethoxysilane, 6 parts by mass of perfluoro-n-propyl vinyl ether, and 0.9 parts by mass of tert-butyl peroxypentanoate are added to a mixed solvent of 55 parts by mass of butyl acetate and propylene glycol methyl ether acetate in a mass ratio of 1:0.8. The mixture is stirred at 500 rpm for 4 hours at a temperature range of 100–105 °C. The temperature is then lowered to 85–90 °C, and 6 parts by mass of hydrogenated rosin glycerol ester and 0.2 parts by mass of organic bismuth catalyst are added. The mixture is stirred at 500 rpm for 4 hours (and the reaction is maintained until the acid value is <5 mg). KOH / g); cool to 40℃, add 0.1 part hydroquinone polymerization inhibitor, stir at 500 rpm for 15 min, filter through a 250 mesh filter to obtain fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin.

[0029] The preparation method of the hindered amine-titanium composite curing accelerator includes the following steps: by mass, 65 parts of isopropanol are added to 15 parts of tetraisopropyl titanate under stirring at 250 rpm and mixed evenly. 10 parts of acetylacetone are added dropwise, the temperature is raised to 50-55℃, and the mixture is stirred at 400 rpm for 3 hours. The temperature is then raised to 60-65℃, 6 parts of hindered amine light stabilizer are added, and the mixture is stirred for another 1.5 hours. The mixture is then cooled to room temperature and filtered through a 100-mesh filter to obtain the hindered amine-titanium composite curing accelerator.

[0030] The preparation method of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion includes the following steps: by mass, 70 parts of butyl acetate and 0.5 parts of dispersant (BYK-163) are stirred at 600 rpm for 10 min, 8 parts of fumed silica are added, and the mixture is sheared and stirred at 2000 rpm for 40 min; 10 parts of perfluorooctyl phosphate and 8 parts of perfluoropolyether alcohol are added, and the mixture is stirred at 1000 rpm for 1 h at a temperature range of 50-55℃; the temperature is lowered to 30℃, 1 part of KH-550 silane coupling agent is added, and the mixture is stirred for another 30 min, and allowed to stand to defoam; the mixture is transferred to a sand mill (zirconium bead media) and sand-milled to a fineness of less than 10 μm, and then filtered through a 200-mesh filter to obtain the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion.

[0031] The preparation method of the above-mentioned fluorocarbon modified curable metallic paint includes the following steps: S1: According to the paint composition formula, the mixed solvent, dispersant, and defoamer are stirred at 500 rpm for 15 min; rutile titanium dioxide, zinc phosphate, and barium sulfate are added and sheared and dispersed at 1500 rpm for 40 min, then transferred to a sand mill and sand-milled to a fineness of less than 15 μm; transferred to a paint mixing tank, and fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin and hydroxyl acrylic resin are added under stirring at 600 rpm, and stirring is continued for 20 min; nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, leveling agent, ultraviolet absorber, hindered amine-titanium composite curing accelerator are added, and stirring is continued at 500 rpm for 20 min to obtain the paint composition; S2: When using, mix the paint components and hardener components according to the mass ratio, adjust the viscosity to the application viscosity with the mixed solvent, let stand for 5 minutes, and you will get the metallic paint.

[0032] Example 3 A fluorocarbon-modified curable metallic paint is prepared by mixing paint components and curing agent components at a mass ratio of 100:22 and adjusting the viscosity with a mixed solvent. The paint components include the following raw materials in parts by mass: 53 parts of fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin, 14 parts of hydroxyl acrylic resin, 20 parts of rutile titanium dioxide, 5 parts of zinc phosphate, 8 parts of barium sulfate, 25 parts of nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, 0.8 parts of hindered amine-titanium composite curing accelerator, 0.6 parts of leveling agent, 0.7 parts of dispersant, 0.4 parts of defoamer, 1.2 parts of ultraviolet absorber, and 12 parts of mixed solvent. The curing agent component is a blocked isocyanate curing agent. The mixed solvent is butyl acetate and propylene glycol methyl ether acetate in a mass ratio of 1:1; the leveling agent is BYK-333; the dispersant is BYK-163; the defoamer is BYK-066N; and the ultraviolet absorber is UV-531.

[0033] The preparation method of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin includes the following steps: Under nitrogen protection, in a reactor equipped with a high-efficiency reflux condenser and a pressure balancing device, 23 parts by mass of trifluorochloroethylene, 19 parts by mass of 4-hydroxybutyl vinyl ether, 3 parts by mass of γ-methacryloyloxypropyltrimethoxysilane, 4 parts by mass of perfluoro-n-propyl vinyl ether, and 0.7 parts by mass of tert-butyl peroxypentanoate are added to a 1:1 mixture of butyl acetate and propylene glycol methyl ether acetate. The mixture is stirred at 400 rpm for 3 hours at a temperature of 100–105 °C. The temperature is then lowered to 85–90 °C, and 4 parts by mass of hydrogenated rosin glycerol ester and 0.1 parts by mass of organic bismuth catalyst are added. The mixture is stirred at 400 rpm for 3 hours (and the reaction is maintained until the acid value is <5 mg). KOH / g); cool to 48℃, add 0.05 parts hydroquinone polymerization inhibitor, stir at 400 rpm for 10 min, filter through a 200 mesh filter to obtain fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin.

[0034] The preparation method of the hindered amine-titanium composite curing accelerator includes the following steps: by mass, 70 parts of isopropanol are added to 18 parts of tetraisopropyl titanate under stirring at 200 rpm and mixed evenly. 8 parts of acetylacetone are added dropwise, the temperature is raised to 50-55℃, and the mixture is stirred at 500 rpm for 2 hours. The temperature is then raised to 60-65℃, and 8 parts of hindered amine light stabilizer are added. The mixture is stirred for another 1 hour, cooled to room temperature, and filtered through a 150-mesh filter to obtain the hindered amine-titanium composite curing accelerator.

[0035] The preparation method of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion includes the following steps: 80 parts by mass of butyl acetate and 0.8 parts by mass of dispersant (BYK-163) are stirred at 800 rpm for 15 min, 10 parts by mass of fumed silica are added, and the mixture is dispersed by shearing and stirring at 2500 rpm for 60 min; 12 parts by mass of perfluorooctyl phosphate and 10 parts by mass of perfluoropolyether alcohol are added, and the mixture is stirred at 1200 rpm for 1.5 h at a temperature range of 50-55℃; the temperature is lowered to 38℃, 1.5 parts by mass of KH-550 silane coupling agent are added, and the mixture is stirred for another 40 min, then allowed to stand to defoam; the mixture is transferred to a sand mill (zirconium bead media) and milled to a fineness of less than 10 μm, then filtered through a 250-mesh filter to obtain the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion.

[0036] The preparation method of the above-mentioned fluorocarbon modified curable metallic paint includes the following steps: S1: According to the paint composition formula, the mixed solvent, dispersant, and defoamer are stirred at 600 rpm for 10 min; rutile titanium dioxide, zinc phosphate, and barium sulfate are added and sheared and dispersed at 2000 rpm for 30 min, then transferred to a sand mill and sand-milled to a fineness of less than 15 μm; transferred to a paint mixing tank, and fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin and hydroxyl acrylic resin are added under stirring at 800 rpm, and stirring is continued for 15 min; nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, leveling agent, ultraviolet absorber, hindered amine-titanium composite curing accelerator are added, and stirring is continued at 600 rpm for 15 min to obtain the paint composition; S2: When using, mix the paint components and hardener components according to the mass ratio, adjust the viscosity to the application viscosity with the mixed solvent, and let stand for 10 minutes to obtain metallic paint.

[0037] The coatings in the above embodiments are adjusted to an application viscosity of 20-30 seconds at 25°C (Ford Cup 4).

[0038] Recommended usage methods for the fluorocarbon-modified curable metallic paints prepared in the above embodiments: For use at room temperature: construction environment 15~35℃, humidity <75%, dry film thickness controlled 30~40μm, surface dry 20~30min, hard dry 6~8h, complete curing 7d; Baking application: Bake at 120-140℃ for 30-40 minutes to cure, with a dry film thickness of 30-40μm.

[0039] The raw materials used in the above embodiments are as follows: Hydroxyacrylate resin is from Nantong Fangxin Chemical Co., Ltd., with a hydroxyl value of 100±3 mgKOH / g, model FX-9024. Barium sulfate, passing through a 325-mesh sieve, is from Shanghai Yuejiang Titanium Dioxide Chemical Products Co., Ltd., and is a coating-specific ultrafine modified precipitated barium sulfate. UV-531 is from Nanjing Milan New Materials Co., Ltd. The blocked isocyanate curing agent is Covestro Desmodur BL 3175 SN. 4-Hydroxybutylvinyl ether is from Wuhan Beiguofeng Chemical Co., Ltd., with a purity of 99%. γ-Methacryloxypropyltrimethoxysilane is a silane coupling agent KH-570, from Wuhan Jiyesheng Chemical Co., Ltd., with a purity of over 98%. Perfluoropropylvinyl ether is from Hubei Wande Chemical Co., Ltd., with a purity of 99%. Hydrogenated rosin glycerol ester is from Wuhan Jiyesheng Chemical Co., Ltd. The organobismuth catalyst is from Wuhan Penglei Biotechnology Co., Ltd., and is organobismuth catalyst DY-20, with bismuth carboxylic acid as its main component. The hindered amine light stabilizer, HS-944, is sourced from Hubei Jusheng Technology Co., Ltd., with a purity of 99%. The fumed silica, hydrophobic and with a purity of 99%, with a particle size range below 50nm, is sourced from Hubei Chengfeng Chemical Co., Ltd. Perfluorooctyl phosphate is sourced from Shenzhen Ruijite Biotechnology Co., Ltd. Perfluoropolyether alcohol is sourced from Tianmen Hengchang Chemical Co., Ltd., with a molecular weight of 1000-5000 and a purity of 99%. KH-550 silane coupling agent is sourced from Wuhan Jiyesheng Chemical Co., Ltd., with a purity of 98%. Rutile titanium dioxide, passing through a 325-mesh sieve, is sourced from Jinan Shiji Tongda Chemical Co., Ltd., with a purity of 99%. Zinc phosphate, passing through a 325-mesh sieve, is sourced from Nantong Zhonghe Chemical New Materials Co., Ltd., with a purity of 99%. BYK-320, BYK-306, and BYK-333 are BYK's leveling agents. BYK-163 is BYK's dispersant. BYK-066N is BYK's defoamer. The purity of all other raw materials is above 98%. The sources of the above-mentioned raw materials are merely illustrative examples and are not intended to limit the scope of the present invention.

[0040] Comparative Example 1 The difference from Example 1 is that the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin is changed to 35 parts, and the hydroxyl acrylic resin is changed to 30 parts.

[0041] Comparative Example 2 The difference from Example 1 is that γ-methacryloyloxypropyltrimethoxysilane and perfluoropropyl vinyl ether are not added in the preparation of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin.

[0042] Comparative Example 3 The difference from Example 1 is that in the preparation of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin, the step of "lowering the temperature to 85-90°C, adding 5 parts of hydrogenated rosin glycerol ester and 0.15 parts of organic bismuth catalyst, and stirring at 450 rpm for 3.5 h" is omitted.

[0043] Comparative Example 4 The difference from Example 1 is that perfluorooctyl phosphate is not added in the preparation of the nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion.

[0044] Comparative Example 5 The difference from Example 1 is that no perfluoropolyether alcohol is added in the preparation of the nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion.

[0045] Comparative Example 6 The difference from Example 1 is that perfluorooctyl phosphate and perfluoropolyether alcohol are not added in the preparation of the nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion.

[0046] Comparative Example 7 The difference from Example 1 is that no hindered amine-titanium composite curing accelerator is added.

[0047] Comparative Example 8 The difference from Example 1 is that acetylacetone is not added in the preparation of the hindered amine-titanium composite curing accelerator.

[0048] Each coating was adjusted to a viscosity of 25 seconds at 25°C using its corresponding mixed solvent and a Forco 4 cup viscosity of 25 seconds. The coating film was baked at 130°C for 40 minutes to cure, cooled to room temperature, and then conditioned for 24 hours in an environment with a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%.

[0049] I. Adhesion Test (Cross-cut Test): Refer to GB / T 9286 "Paints and Varnishes - Cross-cut Test". The substrate is Q235 cold-rolled steel sheet, with dimensions of 150mm × 70mm × 0.8mm and a dry paint film thickness of 35μm ± 3μm. Three parallel samples are used in each group. Using a 1mm spacing cross-cut tester, six parallel cutting lines are cut into the paint film extending to the substrate to form a grid. After lightly brushing with a soft brush, 3M 600# tape is used to tightly adhere the film, followed by peeling. The degree of paint film peeling is observed using a 2x magnifying glass, and graded from 0 to 5 according to the standard.

[0050] II. Adhesion Test (Pull-Off Method): Refer to GB / T 5210 "Paints and Varnishes - Pull-Off Method for Adhesion Testing". The substrate is Q235 cold-rolled steel sheet, 150mm × 70mm × 1.0mm in size, with a dry film thickness of 35μm ± 3μm. Three parallel samples are used per group. A tensile testing machine is used, employing a 20mm diameter test column. The test column is bonded to the coating with adhesive, and the column is pulled apart vertically. The breaking strength (MPa) and the nature of the failure are recorded.

[0051] III. Paint Film Hardness Test (Pencil Hardness): Refer to GB / T 6739 "Determination of Paint Film Hardness by Pencil Method". The substrate is Q235 cold-rolled steel sheet, 150mm × 70mm × 0.8mm in size, with a dry paint film thickness of 35μm ± 3μm. Three parallel samples are used per group. Using a drawing pencil of known hardness, the pencil is held at a 45° angle to the paint film and advanced at a speed of 1mm / s for at least 7mm. The test begins with the hardest pencil and continues until a scratch or tear of 3mm or more appears on the paint film. The maximum pencil hardness that cannot cause this defect in the paint film under these conditions is recorded.

[0052] IV. Impact Resistance Test: Refer to GB / T 1732 "Determination of Impact Resistance of Paint Films". The substrate is Q235 cold-rolled steel sheet, dimensions 150mm×50mm×0.8mm, dry paint film thickness 35μm±3μm. Three parallel samples are used per group. A hammer impact tester is used, with a hammer mass of 1kg, a punch diameter of 8mm, and a groove diameter of 10mm. The sample is placed flat on the impact table with the paint film facing upwards, and the impact height is 50cm, with the hammer falling freely. The paint film is observed using a 4x magnifying glass. The result is indicated as "pass" or "fail". If the paint film is intact, it is considered a pass; if cracks or peeling occur, it is considered a fail.

[0053] V. Flexibility Test: Refer to GB / T 6742 "Paints and Varnishes - Bending Test (Cylindrical Shaft)". The substrate is Q235 cold-rolled steel sheet, with dimensions of 150mm × 50mm × 0.8mm and a dry paint film thickness of 35μm ± 3μm. Three parallel samples are used in each group. Using a 2mm diameter shaft, the sample is bent 180° around the shaft within 2s to 3s. The paint film is examined using a 4x magnifying glass, and the result is indicated as "pass" or "fail". If the paint film is intact, it is considered a pass; if cracks or peeling occur, it is considered a fail.

[0054] VI. Water Resistance Test: Refer to Method A of GB / T 1733 "Determination of Water Resistance of Paint Films". The substrate is Q235 cold-rolled steel sheet, 150mm×70mm×1.0mm in size, with a dry paint film thickness of 35μm±3μm. The edges are sealed with a 1:1 mixture of paraffin and rosin. Three parallel samples are used per group. Using a constant temperature water bath, 2 / 3 of the sample area is immersed in deionized water at 23℃±2℃ for 240 hours. After soaking, the sample is removed, dried with filter paper, and left to stand for 1 hour. Observe whether the paint film shows signs of loss of gloss, discoloration, wrinkling, blistering, or peeling. A comprehensive rating is performed according to GB / T 1766-2008.

[0055] VII. Chemical Resistance Testing (Acids, Alkalis, Salts): Refer to Method A (Immersion Method) of GB / T 9274 "Determination of Resistance to Liquid Media in Paints and Varnishes". The substrate is Q235 cold-rolled steel sheet, 150mm × 70mm × 1.0mm in size, with a dry paint film thickness of 35μm ± 3μm, sealed with a 1:1 mixture of paraffin and rosin. Three parallel samples are used per group. Using glass containers, the samples are immersed in 5wt% H2SO4 solution, 5wt% NaOH solution, 5wt% NaCl solution, and xylene at 23℃ ± 2℃, respectively. After immersion for 168 hours, the samples are removed, rinsed with water, blotted dry with filter paper, and left to stand for 1 hour. Observe whether the paint film shows signs of loss of gloss, discoloration, wrinkling, blistering, or peeling, and perform a comprehensive rating according to GB / T 1766-2008.

[0056] 8. Artificial Weathering Resistance Test: Refer to GB / T 1865 "Artificial Weathering and Artificial Radiation Exposure to Filtered Xenon Arc Radiation for Paints and Varnishes" Method 1. The substrate is Q235 cold-rolled steel sheet, 150mm × 70mm × 1.0mm in size, with a dry paint film thickness of 35μm ± 3μm. Three parallel samples are used per group. A xenon lamp aging test chamber is used, with a sunlight filter system and a 340nm irradiance of 0.51W / (m²). 2 The test was conducted at a blackboard temperature of 65℃±3℃, with a cycle of 102 minutes of light exposure followed by 18 minutes of spraying. The total test duration was 5000 hours. After the test, the paint film was observed for any loss of gloss, discoloration, chalking, wrinkling, blistering, or peeling, and a comprehensive rating was given in accordance with GB / T 1766-2008.

[0057] IX. Stain Resistance Test: Refer to the quartz powder / fly ash method in GB / T 9780 "Test Method for Stain Resistance of Architectural Coatings". The substrate is Q235 cold-rolled steel sheet, 150mm×70mm×1.0mm in size, with a dry film thickness of 35μm±3μm. Three parallel samples are used in each group. A reflectometer is used to test the initial reflectance coefficient of the sample. A 1:1 mixture of quartz powder and fly ash staining agent is prepared according to standard and evenly applied to the sample surface. It is dried at 60℃±2℃ for 30 minutes, and the application and drying process is repeated 5 times to complete the staining cycle. The sample is rinsed with clean water at 23℃±2℃ and a pressure of 0.2MPa for 1 minute, with the rinsing nozzle 30cm perpendicular to the sample surface. After drying, the reflectance coefficient is tested. The rate of decrease in reflectance coefficient is calculated, and the average value is taken.

[0058] 10. Low Temperature and High Humidity Film Formation Adaptability Test: The paint film was prepared according to GB / T 1727 "General Method for Preparing Paint Films", and the adhesion test was conducted according to GB / T 9286-2021. The substrate was Q235 cold-rolled steel sheet with dimensions of 150mm×70mm×0.8mm. Curing parameters: The paint film was sprayed and prepared in a constant temperature and humidity chamber under controlled conditions of 5℃±2℃ and 85%±3% relative humidity, and then cured for 7 days. The dry paint film thickness was 35μm±3μm. Three parallel samples were used in each group. After the samples were removed, they were allowed to recover for 24 hours in an environment of 23℃±2℃ and 50%±5% humidity, and then the adhesion was tested and rated according to the cross-cut adhesion test.

[0059] Table 1. Test Results (Average Values) Table 1. Continuing test results (average) The comprehensive high performance of the fluorocarbon modified curing metallic paints in Examples 1 to 3 is mainly due to the organic-inorganic hybrid crosslinking network constructed by the quaternary modified resin, the hindered amine-titanium composite curing accelerator, and the nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion. This network forms a synergistic strengthening effect from five dimensions: film structure, interfacial bonding, curing kinetics, surface properties, and stabilization mechanism. Fluorocarbon and perfluoropolyether segments endow the paint film with extremely low surface energy and high chemical bond energy, achieving basic properties such as weather resistance, chemical corrosion resistance, and self-cleaning at the molecular level. Siloxane segments hydrolyze and condense to form a Si-O-Si inorganic rigid network, which covalently bonds with organic resins, improving the crosslinking density, hardness, heat resistance, and substrate adhesion of the paint film. 4-Hydroxybutylvinyl ether provides hydroxyl functional groups, ensuring complete crosslinking under room temperature and baking conditions. Hydrogenated rosin glycerol ester introduces a fused ring rigid structure and polar ester groups, enhancing the resin's wetting and anchoring ability to metal substrates. The fused ring rigid structure disperses the internal stress of the resin molecular chain, and the polar ester groups form hydrogen bonds with the metal substrate, reducing internal stress cracking caused by paint film curing shrinkage, improving internal stress distribution and enhancing flexibility. At the same time, it improves the compatibility of the resin with pigments, fillers, and additives, reducing internal defects in the paint film. Tetraisopropyl titanate is chelated with acetylacetone to form a stable titanium chelate, which reduces the crosslinking activation energy of hydroxyl groups and isocyanates, accelerates the curing rate, and ensures good film formation even under low temperature and high humidity conditions. After the hindered amine light stabilizer is combined with the titanium center, it captures free radicals generated by photoaging, decomposes peroxides, and forms a synergistic light stabilizing system with the ultraviolet absorber, thus delaying the aging of the paint film. The chelate structure also avoids premature hydrolysis and aggregation of the titanium catalyst, ensuring the application tolerance of the coating. Nano-silica, as rigid particles, enhances the hardness, scratch resistance, and impact resistance of the paint film. Simultaneously, it constructs a nano-scale rough structure on the paint film surface, synergistically achieving superhydrophobicity with low surface energy fluorine components, further improving stain resistance. Fluoroalkyl phosphates anchor nanoparticles to the resin matrix with polar phosphate groups, and the outward orientation of fluoroalkyl groups further reduces surface energy, enhancing stain resistance and hydrophobic / oleophobic properties. Perfluorinated polyether alcohols act as lubricants, compatibilizers, and reduce interfacial tension, improving the leveling properties of the paint film and the dispersion stability of nanoparticles. KH-550 silane coupling agent achieves chemical bonding between inorganic nanoparticles and organic resins, eliminating interfacial defects and improving the toughness, media resistance, and shielding performance of the paint film. In summary, high crosslinking density enhances the media shielding performance of the paint film, low surface energy achieves self-cleaning, the inorganic-organic hybrid structure balances hardness and toughness, the light-stabilized system ensures long-term weather resistance, and the curing accelerator solves the problem of low-temperature, high-humidity film formation. Ultimately, this results in a synergistic effect of high adhesion, high hardness, high weather resistance, high chemical resistance, self-cleaning, and easy application.

[0060] In Comparative Example 1, the amount of quaternary modified resin was reduced while the amount of hydroxyl acrylic resin was increased. The decrease in the proportion of quaternary modified resin led to a significant reduction in the content of functional segments such as fluorocarbons, siloxanes, and perfluoropolyethers in the paint film. The paint film was mainly composed of ordinary hydroxyl acrylic resin, resulting in a comprehensive decline in performance. The lack of functional segments significantly increased the surface energy of the paint film, weakening its resistance to staining, weathering, and chemical media. The reduced proportion of the Si-O-Si inorganic rigid network decreased the hardness, cohesion, and adhesion to the substrate of the paint film. The reduction in polar anchoring groups weakened the resin's wetting and bonding ability to the metal substrate, resulting in insufficient film-forming driving force under low temperature and high humidity conditions, and poor resin flowability and wettability. The poor light aging resistance and solvent resistance of ordinary acrylic resin further exacerbated the deterioration of the paint film's water resistance, acid and alkali resistance, and aging resistance.

[0061] In Comparative Example 2, no γ-methacryloyloxypropyltrimethoxysilane or perfluoropropyl vinyl ether was added during the preparation of the quaternary resin. The resin retained only the fluorocarbon and hydroxyl vinyl ether structures. The absence of the rigid siloxane network and the low surface energy segments of the perfluoroether disrupted the integrity of the resin structure, becoming the core reason for performance degradation. Without siloxane segments, the Si-O-Si inorganic-organic hybrid structure could not be formed, resulting in insufficient toughness and failure to pass the flexibility test. Without perfluoroether segments, the surface energy of the paint film increased, leading to a decrease in weather resistance, acid and alkali resistance, solvent resistance, and self-cleaning properties. The imbalance between the flexibility and rigidity of the resin molecular chains weakened the anchoring ability to the substrate, resulting in decreased adhesion. Under low temperature and high humidity, the resin exhibited extremely poor film-forming and leveling properties, and its aging resistance deteriorated.

[0062] In Comparative Example 3, the hydrogenated rosin glycerol ester modification step was omitted in the preparation of the quaternary resin. The absence of hydrogenated rosin glycerol ester, a key component that combines polar anchoring, toughening, and low-temperature film-forming modification, resulted in significant defects in both the interfacial bonding and internal structure of the paint film. The fused ring structure and polar ester groups of hydrogenated rosin glycerol ester are crucial for enhancing the resin's wetting and anchoring force on the metal substrate. Its absence reduces the adhesion and bonding strength between the paint film and the substrate; the component's role in regulating internal stress and improving toughness disappears, leading to poorer low-temperature film-forming fluidity; simultaneously, its role in improving the compatibility of the resin with pigments, fillers, and additives is lost, resulting in increased micro-defects within the paint film, decreased density, easier penetration by water and corrosive media, and a decline in water resistance, chemical resistance, and aging resistance.

[0063] In Comparative Example 4, the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion was prepared without the addition of fluoroalkyl phosphate. The absence of this key component for fluorine surface modification and nanoparticle anchoring resulted in deterioration of both the surface and mechanical properties of the coating film. Fluoroalkyl phosphate is one of the core components for achieving low surface energy in the coating film; its absence increases the surface energy and reduces stain resistance. The anchoring effect of its polar heads on the nano-silica and resin matrix disappears, leading to decreased nanoparticle dispersibility and easy agglomeration, forming stress concentration points within the coating film and deteriorating mechanical properties. Nanoparticle agglomeration causes interfacial defects in the coating film, reducing shielding performance and allowing penetration of corrosive media such as water, acids, and alkalis, resulting in a slight deterioration in water and chemical resistance. Furthermore, the uniformity of the coating film formation is poor under low temperature and high humidity conditions.

[0064] In Comparative Example 5, no perfluoropolyether alcohol was added during the preparation of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion. The absence of this functional component, which combines the lubricating, compatibilizing, and surface tension-reducing properties of fluoroethers, affected the interfacial bonding, leveling, and surface properties of the paint film. The perfluoropolyether alcohol's effect on reducing interfacial tension and improving leveling was reduced; its ability to improve the compatibility between fluorine components and resin was also lost, leading to uneven fluorine distribution on the paint film surface, increased surface energy, and decreased stain resistance, hydrophobicity, and oleophobicity. Simultaneously, the increased interfacial defects resulted in decreased film shielding, allowing water and corrosive media to penetrate more easily, and reducing water resistance, chemical resistance, and aging resistance.

[0065] In the preparation of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion in Comparative Example 6, neither fluoroalkyl phosphate nor perfluoropolyether alcohol was added. The simultaneous absence of these two core functional components caused the composite dispersion to lose its fluorine modification, nanoparticle anchoring dispersion, and inorganic-organic interfacial compatibility. Furthermore, the cumulative effect of performance degradation from the absence of both components was far greater than the impact of the absence of a single component. This resulted in serious problems with interfacial defects, structural uniformity, and surface properties of the paint film, leading to a deterioration in various properties. Without fluoroalkyl phosphate, the anchoring bridge between nanoparticles and resin, and the low surface energy fluorine source, led to the agglomeration of nano-silica, forming stress concentration points and causing a sharp drop in the film's shielding properties and surface hydrophobicity. Without perfluoropolyether alcohol, the compatibilizing, lubricating, and interfacial tension-reducing effects were lost, resulting in poor nanoparticle dispersion stability, decreased coating leveling properties, and a lack of compatibility between the fluorine component and resin, leading to uneven fluorine distribution in the paint film and a significant increase in interfacial defects. The combined absence of both prevents nano-silica from playing a reinforcing role, resulting in the formation of micropores inside the paint film, allowing water and corrosive media to easily penetrate and significantly reducing its resistance to water and chemical corrosion. Aggregated particles cause stress concentration, causing the paint film to fail the flexibility test. The surface energy of the paint film increases sharply, deteriorating its stain resistance. The inorganic-organic interface bonding force is greatly weakened, resulting in decreased adhesion and poor adaptability to film formation under low temperature and high humidity conditions. At the same time, the paint film has insufficient leveling and density, allowing ultraviolet light to easily penetrate and causing resin aging, which also significantly deteriorates its weather resistance.

[0066] Comparative Example 7 did not include a hindered amine-titanium composite curing accelerator. Lacking a dual-functional component that combines efficient curing catalysis and in-situ light stabilization, the crosslinking reaction between hydroxyl groups and isocyanates resulted in high activation energy and a slow reaction rate due to the absence of a catalyst. This led to insufficient crosslinking density and compactness of the paint film, making it susceptible to penetration by water, gas, and corrosive media, resulting in decreased water resistance, chemical resistance, and aging resistance. Furthermore, the crosslinking reaction was difficult to fully proceed under low temperature and high humidity conditions, leading to incomplete film formation. Without a hindered amine light stabilizer, the paint film could not effectively capture free radicals generated during photoaging, resulting in accelerated chain breakage and oxidative degradation, and premature loss of gloss and chalking. Insufficient crosslinking also slightly reduced the film's cohesion, and the hardness and adhesion were slightly weaker than in the previous example.

[0067] In Comparative Example 8, no acetylacetone was added during the preparation of the hindered amine-titanium composite curing accelerator. The titanate ester was not subjected to acetylacetone chelation stabilization treatment, resulting in uncontrolled catalytic activity and decreased storage and application stability. Without the protection of acetylacetone, tetraisopropyl titanate readily undergoes premature hydrolysis and condensation with moisture and hydroxyl groups in the system, forming agglomerated particles. This leads to uneven catalytic efficiency distribution, resulting in localized over-crosslinking and under-crosslinking of the paint film, causing a decrease in density. Catalyst agglomeration within the paint film forms microscopic defects. Premature hydrolysis also reduces the coating's application stability and slightly affects the film's leveling properties. However, because the core roles of titanium catalysis and hindered amine photostabilization are still retained in the system, the overall performance degradation is far less than in the comparative example where other core components were modified.

Claims

1. A fluorocarbon-modified curable metallic paint, characterized in that, The metallic paint is made by mixing paint components and curing agent components at a mass ratio of 100:18-22, and adjusting the viscosity with a mixed solvent. The paint components include the following raw materials in parts by mass: 50-53 parts of fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin, 12-14 parts of hydroxyl acrylic resin, 16-20 parts of rutile titanium dioxide, 3-5 parts of zinc phosphate, 6-8 parts of barium sulfate, 20-25 parts of nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, 0.5-0.8 parts of hindered amine-titanium composite curing accelerator, 0.3-0.6 parts of leveling agent, 0.4-0.7 parts of dispersant, 0.2-0.4 parts of defoamer, 0.8-1.2 parts of ultraviolet absorber, and 10-12 parts of mixed solvent. The curing agent component is a blocked isocyanate curing agent.

2. The fluorocarbon-modified curable metallic paint according to claim 1, characterized in that, The viscosity of the mixed solvent is adjusted to 20-30 seconds of Forecast cup viscosity; the mixed solvent is butyl acetate to propylene glycol methyl ether acetate in a mass ratio of 1:0.8-1; the leveling agent is BYK-320, BYK-306 or BYK-333; the dispersant is BYK-163; the defoamer is BYK-066N; and the ultraviolet absorber is UV-531.

3. The fluorocarbon-modified curable metallic paint according to claim 1, characterized in that, The fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin is prepared by mixing trifluorochloroethylene, 4-hydroxybutyl vinyl ether, γ-methacryloyloxypropyltrimethoxysilane, perfluoropropyl vinyl ether, tert-butyl peroxypentanoate, mixed solvent, hydrogenated rosin glycerol ester, organic bismuth catalyst, and hydroquinone polymerization inhibitor in a mass ratio of (23-24):(19-21):(3-5):(4-6):(0.7-0.9):(50-55):(4-6):(0.1-0.2):(0.05-0.1). The hindered amine-titanium composite curing accelerator is prepared by isopropanol, tetraisopropyl titanate, acetylacetone, and hindered amine light stabilizer in a mass ratio of (65-70):(15-18):(8-10):(6-8). The nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion is prepared by butyl acetate, dispersant, fumed silica, perfluorooctyl phosphate, perfluoropolyether alcohol, and KH-550 silane coupling agent in a mass ratio of (70-80):(0.5-0.8):(8-10):(10-12):(8-10):(1-1.5).

4. The fluorocarbon-modified curable metallic paint according to claim 1, characterized in that, The fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin comprises trifluorochloroethylene, 4-hydroxybutyl vinyl ether, γ-methacryloyloxypropyltrimethoxysilane, perfluoropropyl vinyl ether, tert-butyl peroxypentanoate, mixed solvent, hydrogenated rosin glycerol ester, organobismuth catalyst, and hydroquinone polymerization inhibitor in the following proportions: (23-24): (19-21): (3-5): (4-6): (0.7-0.9): (50-55): ( The following mixture was prepared by mixing trifluorochloroethylene, 4-hydroxybutyl vinyl ether, γ-methacryloyloxypropyltrimethoxysilane, perfluoropropyl vinyl ether, and tert-butyl peroxypentanoate in a mass ratio of 4–6): (0.1–0.2): (0.05–0.1). The mixture was stirred at 100–105 °C for 3–4 h, and then hydrogenated rosin glycerol ester and organic bismuth catalyst were added at 85–90 °C and stirred for 3–4 h. Finally, hydroquinone polymerization inhibitor was added below 50 °C and stirred to obtain the final product.

5. The fluorocarbon-modified curable metallic paint according to claim 4, characterized in that, The preparation method of the fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin includes the following steps: In parts by weight, add 23-24 parts of trifluorochloroethylene, 19-21 parts of 4-hydroxybutyl vinyl ether, 3-5 parts of γ-methacryloyloxypropyltrimethoxysilane, 4-6 parts of perfluoro-n-propyl vinyl ether, and 0.7-0.9 parts of tert-butyl peroxypentanoate to 50-55 parts of butyl acetate and propylene glycol methyl ether acetate. In a mixed solvent with a mass ratio of 1:0.8 to 1, the mixture is stirred at 100 to 105°C for 3 to 4 hours, then cooled to 85 to 90°C. 4 to 6 parts of hydrogenated rosin glycerol ester and 0.1 to 0.2 parts of organic bismuth catalyst are added, and the mixture is stirred for 3 to 4 hours. The mixture is then cooled to below 50°C, and 0.05 to 0.1 parts of hydroquinone polymerization inhibitor are added. The mixture is stirred for 10 to 15 minutes and filtered to obtain a fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin.

6. The fluorocarbon-modified curable metallic paint according to claim 1, characterized in that, The hindered amine-titanium composite curing accelerator is prepared by stirring isopropanol, tetraisopropyl titanate, acetylacetone, and hindered amine light stabilizer in a mass ratio of (65-70):(15-18):(8-10):(6-8).

7. The fluorocarbon-modified curable metallic paint according to claim 6, characterized in that, The preparation method of the hindered amine-titanium composite curing accelerator includes the following steps: 65-70 parts by weight of isopropanol and 15-18 parts by weight of tetraisopropyl titanate are mixed, 8-10 parts by weight of acetylacetone are added dropwise, the mixture is stirred at 50-55°C for 2-3 hours, 6-8 parts by weight of hindered amine light stabilizer are added at 60-65°C and stirred for 1-1.5 hours, and then filtered to obtain the hindered amine-titanium composite curing accelerator.

8. The fluorocarbon-modified curable metallic paint according to claim 1, characterized in that, The nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion is prepared by mixing butyl acetate, dispersant, fumed silica, perfluorooctyl phosphate, perfluoropolyether alcohol, and KH-550 silane coupling agent in a mass ratio of (70-80):(0.5-0.8):(8-10):(10-12):(8-10):(1-1.5). After stirring butyl acetate and dispersant, fumed silica is added and stirred for dispersion. Perfluorooctyl phosphate and perfluoropolyether alcohol are added and stirred at 50-55°C. KH-550 silane coupling agent is added below 40°C and stirred. The mixture is then milled to a fineness of less than 10 μm.

9. The fluorocarbon-modified curable metallic paint according to claim 8, characterized in that, The preparation method of the nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion includes the following steps: by weight, 85-90 parts of butyl acetate and 0.5-0.8 parts of dispersant are stirred, and 8-10 parts of fumed silica are added and stirred to disperse; 3-4 parts of perfluorooctyl phosphate and 1-2 parts of perfluoropolyether alcohol are added, and the mixture is stirred at 50-55°C for 1-1.5 hours. Add 1 to 1.5 parts of KH-550 silane coupling agent at a temperature below 40°C and stir. Grind the mixture to a fineness of less than 10 μm and filter to obtain a nano-silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion.

10. The method for preparing a fluorocarbon-modified curable metallic paint according to claim 1, characterized in that, Includes the following steps: S1: According to the paint composition formula, mix the solvent, dispersant, and defoamer, add rutile titanium dioxide, zinc phosphate, and barium sulfate for shear dispersion, and mill to a fineness of less than 15μm; add fluorocarbon-siloxane-perfluoropolyether-hydrogenated rosin quaternary modified resin and hydroxyl acrylic resin while stirring, add nano silica-fluoroalkyl phosphate-perfluoropolyether composite dispersion, leveling agent, ultraviolet absorber, and hindered amine-titanium composite curing accelerator while stirring to obtain the paint composition; S2: When using, mix the paint components and hardener components according to the mass ratio, adjust the viscosity with the mixed solvent to the Ford cup viscosity of 20-30 seconds, let stand, and you will get the metallic paint.

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