A weather-resistant one-coat paint and a method for preparing the same

Abstract

The present application relates to the technical field of paint, and especially relates to a weather-resistant one-coat paint and a preparation method thereof. The paint comprises component A and component B; the mass ratio of the component A to the component B is (25-30):3; according to weight parts, the component A comprises the following raw materials: 20-30 parts of hydroxyl acrylic acid resin, 10-20 parts of organic solvent, 25-35 parts of pigment, 5-15 parts of flame retardant, 1-5 parts of modified graphene and 1-4 parts of additive; and the component B is a solution of aliphatic polyisocyanate. The paint has excellent bacteriostasis, flame retardation, weather resistance and corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a weather-resistant topcoat coating and its preparation method. Background Technology

[0002] In the field of construction machinery, the coating process is a crucial step in ensuring the corrosion resistance of equipment and extending its service life. Currently, the industry mainstream adopts a multi-step process: "substrate sandblasting - primer spraying - putty application - topcoat spraying." This traditional process requires multiple rounds of surface treatment and coating curing, resulting in a lengthy overall construction cycle and significantly increased coating costs. Furthermore, strict control over the compatibility of the primer and topcoat is necessary; poor interlayer adhesion can easily lead to problems such as coating wrinkling and peeling. In addition, for some precision components, irregularly shaped structures, or workpieces in on-site maintenance scenarios, sandblasting cannot be performed due to construction environment and structural limitations. In these cases, a high-adhesion special primer must be applied, further increasing the complexity of the process and cost.

[0003] To address these challenges, integrated primer and topcoat coatings have emerged. These coatings achieve both protective and decorative functions with a single coat, effectively avoiding interlayer compatibility issues and significantly simplifying the coating process. However, existing integrated primer and topcoat coatings still have several technical shortcomings: firstly, their weather resistance is significantly deficient, easily fading and chalking under long-term outdoor ultraviolet radiation; secondly, for special operating scenarios such as mines and tunnels, the coating must also possess flame-retardant properties, a requirement that existing integrated primer and topcoat coatings generally fail to meet, limiting their widespread application. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, one of the objectives of this invention is to provide a weather-resistant topcoat that combines the properties of a base and a topcoat, and has excellent flame retardancy and weather resistance.

[0005] The second objective of this invention is to provide a method for preparing a weather-resistant topcoat coating that is simple in process.

[0006] One of the objectives of this invention is achieved through the following technical solution:

[0007] A weather-resistant topcoat coating comprises component A and component B; the mass ratio of component A to component B is (25-30):3.

[0008] By weight, component A comprises the following raw materials: 20-30 parts of hydroxyl acrylic resin, 10-20 parts of organic solvent, 25-35 parts of pigment, 5-15 parts of flame retardant, 1-5 parts of modified graphene, and 1-4 parts of additives. Component B is an aliphatic polyisocyanate solution.

[0009] The preparation process of the modified graphene is as follows:

[0010] S1. Carboxylated graphene was added to acetone, and 1-hydroxybenzotriazole and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added at 0-5℃. After stirring, bis(2-chloroethyl)amine hydrochloride was added and reacted at room temperature. After the reaction was completed, the mixture was purified to obtain chlorine-containing functionalized graphene.

[0011] S2. The chlorine-containing functionalized graphene is added to acetonitrile, and then compound A is added to react. After the reaction is completed, the graphene is purified to obtain the modified graphene.

[0012] The structural formula of compound A is as follows:

[0013] .

[0014] This invention first prepares chlorine-containing functionalized graphene by reacting carboxylated graphene with bis(2-chloroethyl)amine hydrochloride; then, it undergoes a quaternization reaction with compound A to finally obtain the target modified graphene (wherein compound A is prepared by amination reaction of 4-nitro-1,8-naphthalenedicarboxylic anhydride and 4-methylaminopyridine).

[0015] More preferably, the aliphatic polyisocyanate solution is Desmodur® N75MPA / X.

[0016] Preferably, in step S1, the mass ratio of carboxylated graphene, bis(2-chloroethyl)amine hydrochloride, 1-hydroxybenzotriazole, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is 0.2:(1-3):(0.2-0.5):(0.25-0.65); the stirring time is 45-60 min; and the reaction time is 12-24 h.

[0017] Preferably, in step S2, the mass ratio of the chlorine-containing functionalized graphene to compound A is 1:(18-56); the reaction temperature is 75-85℃ and the reaction time is 24-36h.

[0018] Preferably, the preparation process of compound A is as follows:

[0019] 4-Nitro-1,8-naphthalenedicarboxylic anhydride, triethylamine, and 4-methylaminopyridine were added to ethanol, refluxed, and then purified to obtain compound A.

[0020] Preferably, the ratio of 4-nitro-1,8-naphthalenedicarboxylic anhydride, 4-methylaminopyridine, and triethylamine is 1 mmol:(1.2-1.5) mmol:(100-150) μL; and the reflux reaction time is 8-10 h.

[0021] Preferably, the flame retardant is prepared by the following method:

[0022] a. Add 4-(azidomethyl)phenol and potassium carbonate to acetone, then add an acetone solution of dichlorodiphenylsilane to react. After the reaction is complete, purify to obtain intermediate 1;

[0023] The structural formula of intermediate 1 is as follows:

[0024]

[0025] b. Add intermediate 1 and 3,3,3-triphenylpropyne to tetrahydrofuran, then add sodium ascorbate solution and copper sulfate solution, react at room temperature, and purify after the reaction is complete to obtain the flame retardant; the structural formula of the flame retardant is as follows:

[0026] .

[0027] This invention introduces an azide group into the molecular structure by reacting dichlorodiphenylsilane with 4-(azidomethyl)phenol; then, the azide group undergoes a click chemical reaction with 3,3,3-triphenylpropyne to finally obtain the flame retardant.

[0028] Preferably, in step a, the molar ratio of dichlorodiphenylsilane, 4-(azidomethyl)phenol, and potassium carbonate is 8:(16-18):(16-18); the concentration of the acetone solution of dichlorodiphenylsilane is 0.25-0.3 mol / L; the reaction temperature is 40-45℃, and the reaction time is 36-48 h.

[0029] Preferably, in step b, the molar ratio of intermediate 1, 3,3,3-triphenylpropyne, sodium ascorbate, and copper sulfate is 1:(2.2-2.5):(0.4-0.5):(0.2-0.25); the concentration of the sodium ascorbate solution is 1 mol / L; the concentration of the copper sulfate solution is 0.1 mol / L; and the reaction time at room temperature is 36-48 h.

[0030] Preferably, the organic solvent is butyl acetate or ethylene glycol ethyl ether acetate; the hydroxyl value of the hydroxyl acrylic resin is between 55-75 mg KOH / g, and the solid content is 73-77%; by weight, the additives include the following raw materials: 0.5-2 parts of dispersant, 0.2-1 parts of anti-settling agent, and 0.3-1 parts of leveling agent; the leveling agent is a fluorinated modified polyacrylate copolymer; the pigment is rutile titanium dioxide; the dispersant is BYK-110 or BYK-P104S; and the anti-settling agent is Degussa R972.

[0031] More preferably, the hydroxyl acrylic resin is Zhanxin hydroxyl acrylic resin SM2704 / 75BACX; the pigment is Longbai 996; and the leveling agent is Deqian Hemings 837 leveling agent.

[0032] The second objective of this invention is achieved by the following technical solution:

[0033] The preparation method of the above-mentioned weather-resistant topcoat coating includes the following steps:

[0034] Weigh the raw materials, mix 50% of hydroxyl acrylic resin, 60-65% of organic solvent and dispersant evenly, then add pigment, modified graphene, flame retardant and anti-settling agent in sequence, heat and grind to disperse for 20-30 minutes, then add the remaining hydroxyl acrylic resin, remaining organic solvent and leveling agent in sequence, stir evenly to obtain component A; mix component A and component B evenly according to the mass ratio to obtain the weather-resistant topcoat combined coating.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. The coating of the present invention has excellent antibacterial, flame retardant, weather resistant and anticorrosive properties.

[0037] 2. This invention enhances the weather resistance, antibacterial properties, and corrosion resistance of coatings by adding modified graphene. Specifically, graphene itself can block some ultraviolet rays through physical shielding and ultraviolet scattering; simultaneously, the nitronaphthalene groups grafted onto the surface of the modified graphene have strong ultraviolet absorption capabilities. The synergistic effect of these two elements effectively inhibits the degradation and damage of the coating by ultraviolet light, thus endowing the coating with excellent weather resistance. Furthermore, the pyridinium ions generated from the quaternization reaction of the modified graphene possess strong antibacterial activity. By disrupting the cell membrane structure of microorganisms and inhibiting their metabolism and reproduction, this not only gives the coating excellent antibacterial properties but also blocks the erosion of the coating and substrate by microbial metabolites, thereby significantly improving its resistance to microbial corrosion.

[0038] 3. This invention improves the flame retardancy of the coating by adding a flame retardant. Specifically, the polybenzene ring structure in the flame retardant molecule helps to form a stable aromatic carbon skeleton. After being heated, silicon migrates to the surface, promoting the formation of a dense and stable silicon-carbon composite carbon layer, effectively isolating oxygen and heat transfer, and inhibiting the spread of combustion. At the same time, the triazole ring releases inert gas during thermal decomposition, diluting the oxygen concentration in the combustion zone, achieving a dual effect of flame retardancy in both the condensed phase and the gas phase.

[0039] 4. This invention enhances the corrosion resistance and antibacterial effect of the coating by adding a flame retardant. Specifically, the triazole group generated by the click reaction in the flame retardant molecule can form coordination bonds with the surface of the metal substrate through lone pair electrons; the benzene ring structure introduced by 3,3,3-triphenylpropyne enhances the conjugation effect of the triazole ring, further improving its coordination stability with the metal substrate, thereby forming a dense protective film on the metal surface, effectively blocking the penetration of corrosive media such as moisture and salt, and significantly improving the corrosion resistance of the coating. In addition, the triazole heterocyclic structure in the flame retardant molecule can also disrupt the integrity of microbial cell membranes, further enhancing the antibacterial effect of the coating. At the same time, the polar groups and benzene ring structure contained in the molecule can form hydrogen bonds and π-π stacking interactions with the hydroxyl acrylic resin and isocyanate curing agent in the coating system, significantly improving their dispersibility and compatibility in the system, avoiding problems such as phase separation and uneven coating. Attached Figure Description

[0040] Figure 1 The image shows the infrared spectrum of the modified graphene obtained in Example 4, where curve 1 is the infrared spectrum of carboxylated graphene, curve 2 is the infrared spectrum of chlorine-containing functionalized graphene, and curve 3 is the infrared spectrum of modified graphene. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Specific conditions not specified in the embodiments shall be performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0042] In this invention, the hydroxyl acrylic resin is Zhanxin hydroxyl acrylic resin SM2704 / 75BACX;

[0043] The pigment is Longbai 996; the organic solvent is butyl acetate;

[0044] The leveling agent is Deqian Hemings 837 leveling agent; the dispersant is BYK-110.

[0045] The aliphatic polyisocyanate solution was Desmodur® N75MPA / X; the anti-settling agent was Degussa R972.

[0046] Example 1

[0047] Example 1 provides a compound A, prepared by the following method:

[0048]

[0049] The 4-nitro-1,8-naphthalenedicarboxylic anhydride, 4-methylaminopyridine, triethylamine, and ethanol were added to ethanol at a ratio of 1 mmol:1.4 mmol:120 μL:19 mL. The mixture was refluxed for 9 h, and the reaction solution was concentrated by rotary evaporation. The residue was purified by column chromatography to obtain compound A (yield 76.9%). The NMR and mass spectrometry results of compound A are as follows:

[0050] 1 HNMR: (C 18 H 11 N3O4, 400MHz, DMSO-d6) δ: 5.17 (s, 2H), 7.33-7.37 (d, 2H), 7.90-7.94 (t, 1H), 8.23-8.27 (d, 1H), 8.49-8.57 (m, 3H), 8.67-8.71 (dd, 1H), 9.05-9.09 (dd, 1H). MS(ESI) m / z=333.07 [M].

[0051] Example 2

[0052] Example 2 provides a compound A, prepared by the following method:

[0053] The 4-nitro-1,8-naphthalenedicarboxylic anhydride, 4-methylaminopyridine, triethylamine, and ethanol were added to ethanol at a ratio of 1 mmol:1.2 mmol:100 μL:18 mL. After reflux for 8 h, the reaction solution was concentrated by rotary evaporation. The residue was purified by column chromatography to obtain compound A (yield 74.7%). The NMR and mass spectrometry results of compound A were the same as in Example 1.

[0054] Example 3

[0055] Example 3 provides a compound A, prepared by the following method:

[0056] The 4-nitro-1,8-naphthalenedicarboxylic anhydride, 4-methylaminopyridine, triethylamine, and ethanol were added to ethanol at a ratio of 1 mmol:1.5 mmol:150 μL:20 mL. After reflux for 10 h, the reaction solution was concentrated by rotary evaporation. The residue was purified by column chromatography to obtain compound A (yield 75.2%). The NMR and mass spectrometry results of compound A were the same as in Example 1.

[0057] Example 4

[0058] Example 4 provides a modified graphene, the preparation process of which is as follows:

[0059]

[0060] S1. Carboxylated graphene, bis(2-chloroethyl)amine hydrochloride, 1-hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and acetone were used in a ratio of 0.2g:2g:0.4g:0.5g:150mL. The carboxylated graphene was ultrasonically dispersed in acetone. 1-hydroxybenzotriazole (CAS:2592-95-2) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (CAS:7084-11-9) were added at 4℃ and stirred for 55min. Then, bis(2-chloroethyl)amine hydrochloride (CAS:821-48-7) was added. After reacting at room temperature for 20h, the reaction solution was filtered. The solid product was washed with ethanol and deionized water in sequence and then dried under vacuum to obtain chlorine-containing functionalized graphene.

[0061] S2. The chlorine-containing functionalized graphene, compound A, and acetonitrile were ultrasonically dispersed in acetonitrile at a ratio of 0.1 g: 4 g: 160 mL. Then, compound A from Example 1 was added, and the mixture was reacted at 80 °C for 30 h. The reaction solution was filtered, the solid product was washed with acetonitrile, and vacuum dried to obtain modified graphene.

[0062] Example 5

[0063] Example 5 provides a modified graphene, the preparation process of which is as follows:

[0064] S1. Carboxylated graphene, bis(2-chloroethyl)amine hydrochloride, 1-hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and acetone were used in a ratio of 0.2g:1g:0.2g:0.25g:100mL. The carboxylated graphene was ultrasonically dispersed in acetone. 1-hydroxybenzotriazole and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added at 0℃ and stirred for 60 min. Then, bis(2-chloroethyl)amine hydrochloride was added. After reacting at room temperature for 12 h, the reaction solution was filtered. The solid product was washed with ethanol and deionized water in sequence and then dried under vacuum to obtain chlorine-containing functionalized graphene.

[0065] S2. The chlorine-containing functionalized graphene, compound A, and acetonitrile were ultrasonically dispersed in acetonitrile at a ratio of 0.1 g: 1.8 g: 100 mL. Then, compound A from Example 2 was added, and the reaction was carried out at 75 °C for 36 h. The reaction solution was filtered, the solid product was washed with acetonitrile, and vacuum dried to obtain modified graphene.

[0066] Example 6

[0067] Example 6 provides a modified graphene, the preparation process of which is as follows:

[0068] S1. Carboxylated graphene, bis(2-chloroethyl)amine hydrochloride, 1-hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and acetone were used in a ratio of 0.2g:3g:0.5g:0.65g:200mL. The carboxylated graphene was ultrasonically dispersed in acetone. 1-hydroxybenzotriazole and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added at 5°C and stirred for 45 min. Then, bis(2-chloroethyl)amine hydrochloride was added. After reacting at room temperature for 24 h, the reaction solution was filtered. The solid product was washed successively with ethanol and deionized water and dried under vacuum to obtain chlorine-containing functionalized graphene.

[0069] S2. The chlorine-containing functionalized graphene, compound A, and acetonitrile were ultrasonically dispersed in acetonitrile at a ratio of 0.1 g: 5.6 g: 200 mL. Then, compound A from Example 3 was added, and the mixture was reacted at 85 °C for 24 h. The reaction solution was filtered, the solid product was washed with acetonitrile, and vacuum dried to obtain modified graphene.

[0070] Example 7

[0071] Example 7 provides a flame retardant, prepared by the following method:

[0072]

[0073] a. Using dichlorodiphenylsilane, 4-(azidomethyl)phenol, and potassium carbonate in a ratio of 8 mmol:17 mmol:17 mmol, 4-(azidomethyl)phenol (CAS: 55116-31-9) and potassium carbonate (K2CO3) were added to acetone, with the concentration of 4-(azidomethyl)phenol in acetone being 0.32 mol / L. Then, a 0.27 mol / L solution of dichlorodiphenylsilane in acetone was added. After reacting at 42 °C for 40 h, the reaction solution was filtered, and the solid product was washed successively with deionized water and acetone, and dried under vacuum to obtain intermediate 1 (yield 80.3%). The NMR and mass spectrometry results of intermediate 1 are as follows:

[0074] 1 HNMR: (C 26 H 22 N6O2Si, 400MHz, DMSO-d6) δ: 2.67 (s, 4H), 6.74-6.78 (d, 4H), 6.97-7.01 (d, 4H), 7.35-7.39 (m, 6H), 7.44-7.48 (m, 4H). MS (ESI) m / z=478.16[M].

[0075] b. Using intermediate 1, 3,3,3-triphenylpropyne, sodium ascorbate, copper sulfate, and tetrahydrofuran in a ratio of 1 mmol:2.4 mmol:0.45 mmol:0.23 mmol:45 mL, intermediate 1 and 3,3,3-triphenylpropyne were dissolved in tetrahydrofuran. 1 mol / L sodium ascorbate solution and 0.1 mol / L copper sulfate solution were added. After reacting at room temperature for 40 h, the reaction solution was extracted with ethyl acetate / water. The organic phase was concentrated and purified by column chromatography to obtain the flame retardant (yield 80.9%). The NMR and mass spectrometry results of the flame retardant are as follows:

[0076] 1 HNMR: (C 68 H 54 N6O2Si, 400MHz, DMSO-d6) δ: 5.48 (s, 4H), 6.74-6.78 (d, 4H), 6.93-6.97 (d, 4H), 7.08-7.12 (m, 12H), 7.16-7.20 (m, 6H), 7.24-7.28 (m, 12H) 7.35-7.39 (m, 6H), 7.44-7.48 (m, 4H), 7.63 (s, 2H). MS (ESI) m / z=1014.41[M].

[0077] Example 8

[0078] Example 8 provides a flame retardant, prepared by the following method:

[0079] a. Using dichlorodiphenylsilane, 4-(azidomethyl)phenol, and potassium carbonate in a ratio of 8 mmol:16 mmol:16 mmol, 4-(azidomethyl)phenol and K2CO3 were added to acetone, wherein the concentration of 4-(azidomethyl)phenol in acetone was 0.3 mol / L. Then, a 0.25 mol / L solution of dichlorodiphenylsilane in acetone was added. After reacting at 40°C for 48 h, the reaction solution was filtered, and the solid product was washed successively with deionized water and acetone, and dried under vacuum to obtain intermediate 1 (yield 78.8%). The NMR and mass spectrometry results of intermediate 1 were the same as in Example 7.

[0080] b. Using intermediate 1, 3,3,3-triphenylpropyne, sodium ascorbate, copper sulfate, and tetrahydrofuran in a ratio of 1 mmol:2.2 mmol:0.4 mmol:0.2 mmol:40 mL, intermediate 1 and 3,3,3-triphenylpropyne were dissolved in tetrahydrofuran. 1 mol / L sodium ascorbate solution and 0.1 mol / L copper sulfate solution were added. After reacting at room temperature for 36 h, the reaction solution was extracted with ethyl acetate / water. The organic phase was concentrated and purified by column chromatography to obtain the flame retardant (yield 78.6%). The NMR and mass spectrometry results of the flame retardant were the same as in Example 7.

[0081] Example 9

[0082] Example 9 provides a flame retardant, prepared by the following method:

[0083] a. Using dichlorodiphenylsilane, 4-(azidomethyl)phenol, and potassium carbonate in a ratio of 8 mmol: 18 mmol: 18 mmol, 4-(azidomethyl)phenol and K2CO3 were added to acetone, wherein the concentration of 4-(azidomethyl)phenol in acetone was 0.35 mol / L. Then, a 0.3 mol / L solution of dichlorodiphenylsilane in acetone was added. After reacting at 45°C for 36 h, the reaction solution was filtered, and the solid product was washed successively with deionized water and acetone, and dried under vacuum to obtain intermediate 1 (yield 78.7%). The NMR and mass spectrometry results of intermediate 1 were the same as in Example 7.

[0084] b. Using intermediate 1, 3,3,3-triphenylpropyne, sodium ascorbate, copper sulfate, and tetrahydrofuran in a ratio of 1 mmol:2.5 mmol:0.5 mmol:0.25 mmol:50 mL, intermediate 1 and 3,3,3-triphenylpropyne were dissolved in tetrahydrofuran. 1 mol / L sodium ascorbate solution and 0.1 mol / L copper sulfate solution were added. After reacting at room temperature for 48 h, the reaction solution was extracted with ethyl acetate / water. The organic phase was concentrated and purified by column chromatography to obtain the flame retardant (yield 77.6%). The NMR and mass spectrometry results of the flame retardant were the same as in Example 7.

[0085] Example 10

[0086] Example 10 provides a weather-resistant topcoat coating comprising component A and component B; the mass ratio of component A to component B is 28:3; wherein component B is an aliphatic polyisocyanate solution;

[0087] By weight, component A comprises the following raw materials: 25 parts hydroxy acrylic resin, 14 parts organic solvent, 30 parts pigment, 10 parts flame retardant of Example 7, 4 parts modified graphene of Example 4, and 2 parts additives; wherein by weight, the additives comprise the following raw materials: 1 part dispersant, 0.6 parts anti-settling agent, and 0.8 parts leveling agent.

[0088] Example 10 also provides a method for preparing the above-mentioned weather-resistant topcoat coating, comprising the following steps:

[0089] Weigh the raw materials, mix 50% of hydroxyl acrylic resin, 62% of organic solvent and dispersant, and stir evenly at 450 r / min. Then add pigment, modified graphene, flame retardant and anti-settling agent in sequence, heat and grind and disperse at 1800 r / min for 25 min, controlling the grinding temperature ≤60℃ and the grinding fineness ≤10μm. Then add the remaining hydroxyl acrylic resin, remaining organic solvent and leveling agent in sequence, and stir evenly to obtain component A. Mix component A and component B evenly according to the mass ratio to obtain the weather-resistant topcoat coating.

[0090] Example 11

[0091] Example 11 provides a weather-resistant topcoat coating comprising component A and component B; the mass ratio of component A to component B is 25:3; wherein component B is an aliphatic polyisocyanate solution;

[0092] By weight, component A comprises the following raw materials: 20 parts hydroxy acrylic resin, 10 parts organic solvent, 25 parts pigment, 5 parts flame retardant of Example 8, 1 part modified graphene of Example 5, and 1 part additive; wherein by weight, the additive comprises the following raw materials: 0.5 parts dispersant, 0.2 parts anti-settling agent, and 0.3 parts leveling agent.

[0093] Example 11 also provides a method for preparing the above-mentioned weather-resistant topcoat coating, comprising the following steps:

[0094] Weigh the raw materials, mix 50% of hydroxyl acrylic resin, 60% of organic solvent and dispersant, and stir evenly at 400 r / min. Then add pigment, modified graphene, flame retardant and anti-settling agent in sequence, heat and grind and disperse at 1500 r / min for 30 min, controlling the grinding temperature ≤60℃ and the grinding fineness ≤10μm. Then add the remaining hydroxyl acrylic resin, remaining organic solvent and leveling agent in sequence, and stir evenly to obtain component A. Mix component A and component B evenly according to the mass ratio to obtain the weather-resistant topcoat coating.

[0095] Example 12

[0096] Example 12 provides a weather-resistant topcoat coating comprising component A and component B; the mass ratio of component A to component B is 10:1; wherein component B is an aliphatic polyisocyanate solution;

[0097] By weight, component A comprises the following raw materials: 30 parts hydroxy acrylic resin, 20 parts organic solvent, 35 parts pigment, 15 parts flame retardant of Example 9, 5 parts modified graphene of Example 6, and 4 parts additives; wherein by weight, the additives comprise the following raw materials: 2 parts dispersant, 1 part anti-settling agent, and 1 part leveling agent.

[0098] Example 12 also provides a method for preparing the above-mentioned weather-resistant topcoat coating, comprising the following steps:

[0099] Weigh the raw materials, mix 50% of hydroxyl acrylic resin, 62% of organic solvent and dispersant, and stir evenly at 500 r / min. Then add pigment, modified graphene, flame retardant and anti-settling agent in sequence, and heat and grind and disperse at 2000 r / min for 20 min, controlling the grinding temperature ≤60℃ and the grinding fineness ≤10μm. Then add the remaining hydroxyl acrylic resin, remaining organic solvent and leveling agent in sequence, and stir evenly to obtain component A. Mix component A and component B evenly according to the mass ratio to obtain the weather-resistant topcoat coating.

[0100] Comparative Example 1

[0101] Based on Example 10, the modified graphene in component A was replaced with graphene to form Comparative Example 1.

[0102] Comparative Example 2 is formed by omitting the flame retardant in component A from Example 10.

[0103] Experimental Example 1

[0104] The modified graphene prepared in Example 4 was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the results are as follows: Figure 1 As shown.

[0105] Figure 1 This is the infrared spectrum of the modified graphene obtained in Example 4. Curve 1 is the infrared spectrum of carboxylated graphene, curve 2 is the infrared spectrum of chlorine-containing functionalized graphene, and curve 3 is the infrared spectrum of modified graphene. Compared to carboxylated graphene, chlorine-containing functionalized graphene has a higher infrared spectrum at 3500 cm⁻¹. -1 The characteristic absorption peaks of the carboxyl hydroxyl groups around the left and right sides were significantly weakened, while the peaks at 2946 cm⁻¹ were also significantly reduced. -1 2880cm -1 The presence of a characteristic absorption peak of -CH2- at 1340 cm⁻¹ indicates the successful preparation of chlorine-containing functionalized graphene; compared to chlorine-containing functionalized graphene, the modified graphene exhibits a higher absorption peak at 1340 cm⁻¹. -1 The presence of a characteristic absorption peak of -NO2 indicates that the modified graphene was successfully prepared.

[0106] The properties of the coatings prepared in Examples 10-12 and Comparative Examples 1-2 of the present invention will be described below.

[0107] Experimental Example 2

[0108] The performance of the coatings prepared in the embodiments and comparative examples of the present invention was tested, as follows:

[0109] Adhesion (cross-cut test): Tested according to GB / T 9286-2021, and the test results are shown in Table 1;

[0110] Gloss (60°): Tested according to GB / T 9754-2007, and the results are shown in Table 1;

[0111] Water resistance: Tested according to GB / T 1733-1993 at 25℃. The test results are shown in Table 1.

[0112] Alkali resistance: The test was conducted according to GB / T 9274-1988 (Method A), with experimental conditions of 25℃ and 0.1mol / L NaOH. The test results are shown in Table 1.

[0113] Acid resistance: Tested according to GB / T 9274-1988 (Method A), the test conditions were 25℃ and 0.1mol / L H2SO4. The test results are shown in Table 1.

[0114] Salt spray resistance: Tested according to GB / T 1771-2024, and the test results are shown in Table 1;

[0115] Weather resistance: Tested in accordance with GB / T 1865-2009, and the results are shown in Table 1.

[0116] Resistance to damp heat: Tested according to GB / T 1740-2007, and the test results are shown in Table 1;

[0117] Impact resistance: Tested in accordance with GB / T 1732-2020, and the results are shown in Table 1.

[0118] Antibacterial properties: Tested according to HG / T 3950-2007, and the results are shown in Table 1;

[0119] Limiting oxygen index: The test was conducted in accordance with GB / T 2406.1-2008, and the results are shown in Table 1.

[0120]

[0121] As shown in Table 1, the coating obtained in Example 10 exhibits superior weather resistance and antibacterial properties compared to Comparative Example 1. These results indicate that the addition of modified graphene can enhance the weather resistance and antibacterial properties of the coating. Further analysis reveals that graphene itself can block some ultraviolet radiation through physical shielding and ultraviolet scattering; simultaneously, the nitronaphthalene groups grafted onto the surface of the modified graphene possess strong ultraviolet absorption capabilities. The synergistic effect of these two factors effectively inhibits the degradation and damage of the coating by ultraviolet light, thereby endowing the coating with excellent weather resistance. Furthermore, the pyridinium ions generated from the quaternization reaction of the modified graphene possess strong antibacterial activity. By disrupting the cell membrane structure of microorganisms and inhibiting their metabolism and reproduction, the coating not only possesses excellent antibacterial properties but also blocks the erosion of the coating and substrate by microbial metabolites, thus significantly improving its resistance to microbial corrosion.

[0122] Compared with Comparative Example 2, the coating obtained in Example 10 exhibits superior flame retardancy, corrosion resistance, and antibacterial properties. These results indicate that the addition of a flame retardant can enhance the flame retardancy and corrosion resistance of the coating. Further analysis reveals that the flame retardant mechanism is as follows: the polybenzene ring structure in the flame retardant molecule helps form a stable aromatic carbon skeleton; silicon migrates to the surface upon heating, promoting the formation of a dense and stable silicon-carbon composite carbon layer, effectively isolating oxygen and heat transfer, and inhibiting the spread of combustion; simultaneously, the triazole ring releases inert gas during thermal decomposition, diluting the oxygen concentration in the combustion zone, achieving a dual effect of condensed-phase and gas-phase flame retardancy.

[0123] The anti-corrosion mechanism of this flame retardant is as follows: the triazole group generated by the click reaction in the flame retardant molecule can form a coordination bond with the surface of the metal substrate through lone pair electrons; the benzene ring structure introduced by 3,3,3-triphenylpropyne enhances the conjugation effect of the triazole ring, further improving its coordination stability with the metal substrate, thereby forming a dense protective film on the metal surface, effectively blocking the penetration of corrosive media such as moisture and salt, and significantly improving the anti-corrosion performance of the coating.

[0124] Furthermore, the triazole heterocyclic structure in this flame retardant molecule can disrupt the integrity of microbial cell membranes, thus enhancing the antibacterial effect of the coating. Simultaneously, the polar groups and benzene ring structure within the molecule can form hydrogen bonds and π-π stacking interactions with the hydroxyl acrylic resin and isocyanate curing agent in the coating system, significantly improving its dispersibility and compatibility within the system and avoiding problems such as phase separation and uneven coating.

[0125] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A weather-resistant topcoat coating, characterized in that, It includes component A and component B; the mass ratio of component A to component B is (25-30):3; By weight, component A comprises the following raw materials: 20-30 parts of hydroxyl acrylic resin, 10-20 parts of organic solvent, 25-35 parts of pigment, 5-15 parts of flame retardant, 1-5 parts of modified graphene, and 1-4 parts of additives; component B is an aliphatic polyisocyanate solution. The preparation process of the modified graphene is as follows: S1. Carboxylated graphene was added to acetone, and 1-hydroxybenzotriazole and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added at 0-5℃. After stirring, bis(2-chloroethyl)amine hydrochloride was added and reacted at room temperature. After the reaction was completed, the mixture was purified to obtain chlorine-containing functionalized graphene. S2. The chlorine-containing functionalized graphene is added to acetonitrile, and then compound A is added to react. After the reaction is completed, the graphene is purified to obtain the modified graphene. The structural formula of compound A is as follows: ； The structural formula of the flame retardant is as follows: 。 2. The weather-resistant topcoat coating according to claim 1, characterized in that, In step S1, the mass ratio of carboxylated graphene, bis(2-chloroethyl)amine hydrochloride, 1-hydroxybenzotriazole, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is 0.2:(1-3):(0.2-0.5):(0.25-0.65); the stirring time is 45-60 min; and the reaction time is 12-24 h.

3. The weather-resistant topcoat coating according to claim 1, characterized in that, In step S2, the mass ratio of the chlorine-containing functionalized graphene to compound A is 1:(18-56); the reaction temperature is 75-85℃ and the time is 24-36h.

4. The weather-resistant topcoat coating according to claim 3, characterized in that, The preparation process of compound A is as follows: 4-Nitro-1,8-naphthalenedicarboxylic anhydride, triethylamine, and 4-methylaminopyridine were added to ethanol, refluxed, and then purified to obtain compound A.

5. The weather-resistant topcoat coating according to claim 4, characterized in that, The ratio of 4-nitro-1,8-naphthalenedicarboxylic anhydride, 4-methylaminopyridine, and triethylamine is 1 mmol: (1.2-1.5) mmol: (100-150) μL; the reflux reaction time is 8-10 h.

6. The weather-resistant topcoat coating according to claim 1, characterized in that, The flame retardant is prepared as follows: a. Add 4-(azidomethyl)phenol and potassium carbonate to acetone, then add an acetone solution of dichlorodiphenylsilane to react. After the reaction is complete, purify to obtain intermediate 1. The structural formula of intermediate 1 is as follows: b. Add intermediate 1 and 3,3,3-triphenylpropyne to tetrahydrofuran, then add sodium ascorbate solution and copper sulfate solution, react at room temperature, and purify after the reaction is complete to obtain the flame retardant.

7. The weather-resistant topcoat coating according to claim 6, characterized in that, In step a, the molar ratio of dichlorodiphenylsilane, 4-(azidomethyl)phenol, and potassium carbonate is 8:(16-18):(16-18); the concentration of the acetone solution of dichlorodiphenylsilane is 0.25-0.3 mol / L; the reaction temperature is 40-45℃ and the reaction time is 36-48 h.

8. The weather-resistant topcoat coating according to claim 6, characterized in that, In step b, the molar ratio of intermediate 1, 3,3,3-triphenylpropyne, sodium ascorbate, and copper sulfate is 1:(2.2-2.5):(0.4-0.5):(0.2-0.25); the concentration of the sodium ascorbate solution is 1 mol / L; the concentration of the copper sulfate solution is 0.1 mol / L; and the reaction time at room temperature is 36-48 h.

9. The weather-resistant topcoat coating according to claim 1, characterized in that, The organic solvent is butyl acetate or ethylene glycol ethyl ether acetate; the hydroxyl value of the hydroxyl acrylic resin is between 55-75 mg KOH / g, and the solid content is 73-77%; by weight, the additives include the following raw materials: 0.5-2 parts dispersant, 0.2-1 parts anti-settling agent, and 0.3-1 parts leveling agent; the leveling agent is a fluorinated modified polyacrylate copolymer; the pigment is rutile titanium dioxide; the dispersant is BYK-110 or BYK-P104S; and the anti-settling agent is Degussa R972.

10. A method for preparing a weather-resistant topcoat coating according to any one of claims 1-9, characterized in that, Includes the following steps: Weigh the raw materials, mix 50% of hydroxyl acrylic resin, 60-65% of organic solvent and dispersant evenly, then add pigment, modified graphene, flame retardant and anti-settling agent in sequence, heat and grind to disperse for 20-30 minutes, then add the remaining hydroxyl acrylic resin, remaining organic solvent and leveling agent in sequence, stir evenly to obtain component A; mix component A and component B evenly according to the mass ratio to obtain the weather-resistant topcoat combined coating.

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