A multi-component synergistic flame-retardant modified coating and its preparation method

Abstract

The present invention discloses a multi-component synergistic flame-retardant modified coating and a preparation method thereof. It is characterized in that the multi-component synergistic flame-retardant modified coating comprises the following components by weight: 80-100 parts of waterborne epoxy resin, 10-20 parts of multi-component composite flame retardant, 40-50 parts of curing agent, and 10-15 parts of deionized water; the multi-component composite flame retardant is composed of Al(OH)3 modified by organic flame retardant, Mg(OH)2 modified by organic flame retardant, and zinc borate modified by organic flame retardant. The preparation method is to first mix the waterborne epoxy resin, the multi-component composite flame retardant, and deionized water to obtain a prefabricated coating; then mix the prefabricated coating and the curing agent to obtain the multi-component synergistic flame-retardant modified coating. The flame-retardant coating of the present invention has excellent flame-retardant performance.

Description

Technical Field

[0001] The present invention belongs to the field of flame retardant coatings, and in particular relates to a multi-component synergistic flame retardant modified coating and a preparation method thereof. Background Art

[0002] As a material that can curb the spread of fire, flame retardant coatings have been widely used in many fields. According to statistics, more than 80% of fatalities caused by fires are caused by thick smoke and toxic gases released by burning materials. Therefore, flame retardant coatings must not only have excellent flame retardant properties, but also meet the strict requirements of low toxicity and low smoke. In view of this, the use of traditional organic halogen flame retardants is gradually decreasing due to their high toxicity and high smoke generation, while inorganic flame retardants such as Mg(OH)2 and Al(OH)3 have ushered in rapid development due to their non-toxic and smoke-eliminating properties. However, Mg(OH)2 and Al(OH)3 need to be added to a higher proportion (usually up to 50% by mass) to show a good flame retardant effect, which often leads to a decrease in the processing performance of the base resin and a significant loss of mechanical properties.

[0003] As an important member of the inorganic flame retardant system, zinc borate not only has multiple functions such as flame retardancy, carbonization, smoke suppression, smoldering suppression and droplet formation prevention, but also has the advantages of environmental protection, economy and little effect on the mechanical properties of polymers. Current research often adds zinc borate as a flame retardant additive to inorganic flame retardants to form compound flame retardants, aiming to maintain flame retardant properties while reducing the amount of substances such as Mg(OH)2, thereby improving the mechanical properties of the coating. However, directly mixing zinc borate with Mg(OH)2 and / or Al(OH)3 to form a compound flame retardant cannot solve the problem of poor compatibility and easy agglomeration between inorganic nanoparticles and polymer matrices, and when inorganic flame retardants are directly compounded, the amount of flame retardant added is still high. For example, the synergistic effect of zinc borate with Mg(OH)2 and Al(OH)3 in flame retardant EVA (VA content 24%) shows that even in an intumescent flame retardant system, the amount of flame retardant added needs to reach about 30% to achieve an ideal flame retardant effect.

[0004] Therefore, developing efficient surface modification technologies for inorganic particles such as zinc borate, Mg(OH)2, and Al(OH)3 to achieve the dual goals of efficient flame retardancy and good dispersibility, and promoting these flame retardants to form an effective composite system, is of far-reaching significance for promoting their widespread application in the field of flame retardant coatings. Summary of the invention

[0005] The object of the present invention is to overcome the deficiencies of the existing flame retardant coatings mentioned in the above background art. The present invention provides a multi-component synergistic flame retardant modified coating and its preparation method; by effectively surface-modifying zinc borate, Mg(OH)2, and Al(OH)3 respectively, while improving their flame retardant performance and dispersibility, and promoting their effective compounding to form an inorganic-organic-inorganic multi-component synergistic flame retardant, providing a new type of high-performance flame retardant modified material for the field of flame retardant coatings.

[0006] The present invention is realized by the following technical solutions: A multi-component synergistic flame retardant modified coating and its preparation method, characterized in that, by weight, it comprises the following components: 80 - 100 parts of waterborne epoxy resin, 10 - 20 parts of multi-component composite flame retardant, 40 - 50 parts of curing agent, and 10 - 15 parts of deionized water.

[0007] The multi-component composite flame retardant is composed of organically flame retardant modified Al(OH)3, organically flame retardant modified Mg(OH)2, and organically flame retardant modified zinc borate.

[0008] Preferably, the organically flame retardant modified Al(OH)3 (Mg(OH)2) is prepared by the following steps:

[0009] (a) Add epoxy group silane (KH-560) to a mixed solution of water and methanol, and add an organic acid (such as formic acid, acetic acid, etc.), adjust the pH value of the solution to 3.85 - 4.2, and finally add Al(OH)3 (or Mg(OH)2) nanoparticles, ultrasonically disperse evenly, and stir the reaction solution at 50 - 80 o °C for 6 - 10 h, then carry out suction filtration, wash with deionized water for multiple times, and dry to obtain epoxy group modified Al(OH)3 (or Mg(OH)2) nanoparticles; the dosage of each component is: add 200 - 300 mL of a mixed solution of water and methanol with a volume ratio of 2 - 4:1 for every 0.2 - 0.5 g of KH-560, and add 6 - 10 g of inorganic nanoparticles.

[0010] (b) Add the epoxy group modified nanoparticles prepared above to dimethyl sulfoxide, and add 2-amino-4,6-dichloro-S-triazine, ultrasonically disperse the mixture evenly, and then stir the reaction solution at 80 - 120 o °C for 6 - 10 h, then carry out suction filtration, wash with deionized water for multiple times, and dry to obtain organically flame retardant modified Al(OH)3 (or Mg(OH)2) nanoparticles; the dosage of each component is: add 100 - 200 mL of dimethyl sulfoxide for every 1 - 1.5 g of epoxy group modified nanoparticles, and add 0.6 - 1 g of 2-amino-4,6-dichloro-S-triazine.

[0011] Preferably, the organically flame retardant modified zinc borate is prepared by the following steps:

[0012] Disperse zinc borate in deionized water. After ultrasonic dispersion until uniform, add tris(hydroxymethyl)aminomethane hydrochloride to adjust the pH of the solution to 8 - 9. Subsequently, add dopamine hydrochloride, and stir the reaction solution at 20 - 40 o °C for 2 - 4 h, then perform suction filtration. After washing with deionized water multiple times and drying, poly-dopamine-modified zinc borate is obtained; the dosages of each component are as follows: Disperse 1 - 2 g of zinc borate in 100 - 200 ml of deionized water, and add 0.05 - 0.1 g of dopamine hydrochloride.

[0013] Preferably, the multi-component composite flame retardant is prepared by the following steps:

[0014] Disperse organically flame-retardant modified Al(OH)3 and organically flame-retardant modified Mg(OH)2 nanoparticles in ethanol, and obtain a dispersion with a mass fraction of 10 - 20% by ultrasonic homogenization. Further, ultrasonically disperse organically flame-retardant modified zinc borate in the prepared dispersion, stir for 1 - 3 h, filter, retain the solid, wash, and dry to obtain a multi-component composite flame retardant composed of Al(OH)3, Mg(OH)2, organically flame-retardant modifiers (triazine structure and poly-dopamine), and zinc borate; wherein the mass ratio of organically flame-retardant modified Al(OH)3, organically flame-retardant modified Mg(OH)2, and organically flame-retardant modified zinc borate is 4 - 7:4 - 7:1.

[0015] The preparation method of the above multi-component synergistic flame-retardant modified coating of the present invention includes the following steps:

[0016] Mix waterborne epoxy resin, multi-component composite flame retardant, and deionized water to obtain a prefabricated coating; mix the prefabricated coating and a curing agent to obtain a multi-component synergistic flame-retardant modified coating.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) In the composite flame retardant provided by the present invention, zinc borate can form strong and stable chemical bonds with the hydroxyl and amino groups on the surfaces of organically flame-retardant modified Al(OH)3 and Mg(OH)2 nanoparticles through the phenolic and quinone groups in the polydopamine molecules on its surface, forming an effective composite system and promoting the formation of an excellent synergistic flame-retardant effect among the components;

[0019] (2) The multi-component composite flame retardant provided by the present invention can not only construct a multi-component high-efficiency flame-retardant synergistic system of Al(OH)3 - Mg(OH)2 - organically flame-retardant agent (triazine structure and poly-dopamine) - zinc borate, but also at high temperatures, the chlorine atoms in zinc borate and the modifier 2-amino-4,6-dichloro-s-triazine can react to generate a free radical terminator - zinc chloride, and this reaction can further enhance the flame-retardant effect;

[0020] (3) The multi-component composite flame retardant provided by the present invention not only has high-efficiency flame retardant effect but also has good dispersibility, and at the same time solves the influence on the mechanical properties of the coating caused by the large addition and / or serious agglomeration of inorganic flame retardants such as Al(OH)3 and / or Mg(OH)2, effectively promoting the application of inorganic nanoparticles in the field of flame retardant coatings. Specific Embodiments

[0021] The present invention is illustrated by the following examples, but the examples are only used for illustration and cannot be regarded as limiting the scope of the invention or the application method of the invention. Unless otherwise specified, the raw materials of the present invention are all commercially available. In addition, common types of waterborne epoxy resin emulsions and curing agents on the market can be used, and they are used with reference to the operation manuals provided by the manufacturers. Examples

[0022] A multi-component synergistic flame retardant modified coating contains the following components in parts by mass and is prepared by the following steps:

[0023] 80 parts of waterborne epoxy resin, 10 parts of multi-component composite flame retardant, and 10 parts of deionized water are mixed and stirred evenly to obtain a prefabricated coating, and then 40 parts of curing agent are added and stirred evenly to obtain a multi-component synergistic flame retardant modified coating.

[0024] The multi-component composite flame retardant is composed of Al(OH)3 modified by organic flame retardant, Mg(OH)2 modified by organic flame retardant and zinc borate modified by organic flame retardant.

[0025] The Al(OH)3 modified by organic flame retardant and the Mg(OH)2 modified by organic flame retardant are prepared by the following steps:

[0026] a. 0.2 g of epoxy group silane (KH-560) is added to a mixed solution of 200 mL of water and methanol (the volume ratio of the two is 2:1), and formic acid is added to adjust the pH value of the solution to about 4, preferably 3.85-4.2. Finally, 6 g of Al(OH)3 (or Mg(OH)2) nanoparticles are added, and the mixture is ultrasonically dispersed evenly. The reaction solution is stirred at 50 o °C for 10 h, then filtered, washed with deionized water for many times, and dried to obtain epoxy group modified Al(OH)3 (or Mg(OH)2) nanoparticles;

[0027] b. 1 g of the epoxy group modified nanoparticles prepared above is added to 100 mL of dimethyl sulfoxide, and 0.6 g of 2-amino-4,6-dichloro-S-triazine is added. The mixture is ultrasonically dispersed evenly, and then stirred at 80 o °C for 10 h, then filtered, washed with deionized water for many times, and dried to obtain Al(OH)3 (or Mg(OH)2) nanoparticles modified by organic flame retardant;

[0028] The organically flame-retardant modified zinc borate is prepared by the following steps:

[0029] Disperse 1 g of zinc borate in 100 mL of deionized water. After ultrasonic dispersion, add tris(hydroxymethyl)aminomethane hydrochloride to adjust the pH of the solution to 8. Subsequently, add 0.05 g of dopamine hydrochloride, and stir the reaction solution at 20 o °C for 4 h, then perform suction filtration, wash with deionized water multiple times, and dry to obtain zinc borate coated with polydopamine;

[0030] The multi-component composite flame retardant is prepared by the following steps:

[0031] Disperse 4 g of the prepared organically flame-retardant modified Al(OH)3 and 4 g of organically flame-retardant modified Mg(OH)2 nanoparticles in ethanol, and ultrasonic disperse them evenly to obtain a dispersion with a mass fraction of 10%. Further, ultrasonically disperse 1 g of organically flame-retardant modified zinc borate in the prepared dispersion, stir for 3 h, filter, retain the solid, wash, and dry to obtain a multi-component composite flame retardant composed of Al(OH)3, Mg(OH)2, organically flame-retardant modifiers (triazine structures and polydopamine), and zinc borate. Example

[0032] A multi-component synergistic flame-retardant modified coating contains the following components in parts by mass and is prepared by the following steps:

[0033] Mix 90 parts of waterborne epoxy resin, 15 parts of multi-component composite flame retardant, and 12.5 parts of deionized water and stir evenly to obtain a prefabricated coating, and then add 45 parts of curing agent and stir evenly to obtain a multi-component synergistic flame-retardant modified coating.

[0034] Among them, the multi-component composite flame retardant is composed of organically flame-retardant modified Al(OH)3, organically flame-retardant modified Mg(OH)2, and organically flame-retardant modified zinc borate.

[0035] The organically flame-retardant modified Al(OH)3 and organically flame-retardant modified Mg(OH)2 are prepared by the following steps:

[0036] a. Add 0.35 g of epoxy group silane (KH-560) to a mixed solution of 250 mL of water and methanol (the volume ratio of the two is 3:1), add acetic acid, adjust the pH value of the solution to about 4, preferably 3.85 - 4.2, and finally add 8 g of Al(OH)3 (or Mg(OH)2) nanoparticles, ultrasonically disperse them evenly, and stir the reaction solution at 65 o °C for 8 h, then perform suction filtration, wash with deionized water multiple times, and dry to obtain epoxy group modified Al(OH)3 (or Mg(OH)2) nanoparticles;

[0037] b. Add 1.25 g of the above-prepared epoxy-modified nanoparticles to 150 mL of dimethyl sulfoxide, and add 0.8 g of 2-amino-4,6-dichloro-s-triazine. Ultrasonically disperse the mixture evenly, and then stir and react at 100 o °C for 8 h, then perform suction filtration. After washing with deionized water multiple times and drying, organic flame-retardant modified Al(OH)3 (or Mg(OH)2) nanoparticles are obtained;

[0038] The organically flame-retardant modified zinc borate is prepared by the following steps:

[0039] Disperse 1.5 g of zinc borate in 150 mL of deionized water. After ultrasonically dispersing evenly, add tris(hydroxymethyl)aminomethane hydrochloride to adjust the pH of the solution to 8.5. Subsequently, add 0.075 g of dopamine hydrochloride, and stir and react the reaction solution at 30 o °C for 3 h, then perform suction filtration. After washing with deionized water multiple times and drying, zinc borate coated with polydopamine is obtained;

[0040] The multi-component composite flame retardant is prepared by the following steps:

[0041] Disperse 5.5 g of the prepared organically flame-retardant modified Al(OH)3 and 5.5 g of organically flame-retardant modified Mg(OH)2 nanoparticles in ethanol, and ultrasonically disperse evenly to obtain a dispersion with a mass fraction of 15%. Further, ultrasonically disperse 1 g of organically flame-retardant modified zinc borate in the prepared dispersion, stir for 2 h, filter, retain the solid, wash, and dry to obtain a multi-component composite flame retardant composed of Al(OH)3, Mg(OH)2, organically flame-retardant modifiers (triazine structures and polydopamine), and zinc borate. Example

[0042] A multi-component synergistic flame-retardant modified coating contains the following components in parts by mass and is prepared by the following steps:

[0043] Mix 100 parts of waterborne epoxy resin, 20 parts of multi-component composite flame retardant, and 15 parts of deionized water and stir evenly to obtain a prefabricated coating. Then add 50 parts of curing agent and stir evenly to obtain a multi-component synergistic flame-retardant modified coating.

[0044] The multi-component composite flame retardant is composed of organically flame-retardant modified Al(OH)3, organically flame-retardant modified Mg(OH)2, and organically flame-retardant modified zinc borate.

[0045] The organically flame-retardant modified Al(OH)3 and organically flame-retardant modified Mg(OH)2 are prepared by the following steps:

[0046] a. Add 0.5 g of epoxy group silane (KH-560) to a mixed solution of 300 mL of water and methanol (the volume ratio of the two is 4:1), add formic acid, adjust the pH value of the solution to about 4, preferably 3.85 - 4.2, and finally add 10 g of Al(OH)3 (or Mg(OH)2) nanoparticles. After ultrasonic dispersion, stir the reaction solution at 80 o C for 6 h, then perform suction filtration. After washing with deionized water for multiple times and drying, epoxy group modified Al(OH)3 (or Mg(OH)2) nanoparticles are obtained;

[0047] b. Add 1.5 g of the epoxy group modified nanoparticles prepared above to 200 mL of dimethyl sulfoxide, add 1 g of 2-amino-4,6-dichloro-S-triazine, ultrasonically disperse the mixture evenly, and then stir the reaction at 120 o C for 6 h. After suction filtration, wash with deionized water for multiple times and dry to obtain organically flame-retardant modified Al(OH)3 (or Mg(OH)2) nanoparticles;

[0048] The organically flame-retardant modified zinc borate is prepared by the following steps:

[0049] Disperse 2 g of zinc borate in 200 mL of deionized water. After ultrasonic dispersion, add tris(hydroxymethyl)aminomethane hydrochloride to adjust the pH of the solution to 9. Then add 0.1 g of hydrochloric acid dopamine. Stir the reaction solution at 40 o C for 2 h, then perform suction filtration. After washing with deionized water for multiple times and drying, zinc borate coated with polydopamine is obtained;

[0050] The multi-component composite flame retardant is prepared by the following steps:

[0051] Disperse 7 g of the organically flame-retardant modified Al(OH)3 and 7 g of the organically flame-retardant modified Mg(OH)2 nanoparticles in ethanol. After ultrasonic dispersion, a dispersion with a mass fraction of 20% is obtained. Further, ultrasonically disperse 1 g of the organically flame-retardant modified zinc borate in the prepared dispersion, stir for 1 h, filter, retain the solid, wash, and dry to obtain a multi-component composite flame retardant composed of Al(OH)3, Mg(OH)2, organically flame-retardant modifiers (triazine structure and polydopamine), and zinc borate.

[0052] Comparative Example 1

[0053] This comparative example coating contains the following components in parts by mass and is prepared by the following steps: Mix 80 parts of waterborne epoxy resin and 10 parts of deionized water and stir evenly to obtain a prefabricated coating, and then add 40 parts of a curing agent and stir evenly to obtain Comparative Coating 1.

[0054] Comparative Example 2

[0055] The coating of this comparative example contains the following components in parts by mass and is prepared by the following steps: Mix 80 parts of waterborne epoxy resin, 10 parts of compounded flame retardant, and 10 parts of deionized water and stir evenly to obtain a prefabricated coating, then add 40 parts of curing agent and stir evenly to obtain Comparative Coating 2; the compounded flame retardant consists of unmodified Al(OH)3 and Mg(OH)2, and the mass ratio of the two is 1:1.

[0056] Comparative Example 3

[0057] The coating of this comparative example contains the following components in parts by mass and is prepared by the following steps: Mix 80 parts of waterborne epoxy resin, 10 parts of compounded flame retardant, and 10 parts of deionized water and stir evenly to obtain a prefabricated coating, then add 40 parts of curing agent and stir evenly to obtain Comparative Coating 3; the compounded flame retardant consists of unmodified Al(OH)3, Mg(OH)2 and unmodified zinc borate, and the mass ratio of the three is 4:4:1.

[0058] Comparative Example 4

[0059] The coating of this comparative example contains the following components in parts by mass and is prepared by the following steps: Mix 80 parts of waterborne epoxy resin, 10 parts of compounded flame retardant, and 10 parts of deionized water and stir evenly to obtain a prefabricated coating, then add 40 parts of curing agent and stir evenly to obtain Comparative Coating 1; the compounded flame retardant consists of organically flame-retardant modified Al(OH)3, organically flame-retardant modified Mg(OH)2 and unmodified zinc borate, and the mass ratio of the three is 4:4:1.

[0060] The organically flame-retardant modified Al(OH)3 and organically flame-retardant modified Mg(OH)2 are prepared by the following steps:

[0061] a. Add 0.2 g of epoxy silane (KH-560) to 200 mL of a mixed solution of water and methanol (the volume ratio of the two is 2:1), add formic acid, adjust the pH value of the solution to about 4, and finally add 6 g of Al(OH)3 (or Mg(OH)2) nanoparticles, ultrasonically disperse evenly, and stir the reaction solution at 50 o °C for 10 h, then carry out suction filtration, wash with deionized water for multiple times, and dry to obtain epoxy group-modified Al(OH)3 (or Mg(OH)2) nanoparticles;

[0062] b. Add 1 g of the above-prepared epoxy group-modified nanoparticles to 100 mL of dimethyl sulfoxide, add 0.6 g of 2-amino-4,6-dichloro-S-triazine, ultrasonically disperse the mixture evenly, and then stir at 80 o °C for 10 h, then carry out suction filtration, wash with deionized water for multiple times, and dry to obtain organically flame-retardant modified Al(OH)3 (or Mg(OH)2) nanoparticles.

[0063] Comparative Example 5

[0064] The coating of this comparative example contains the following components in parts by mass and is prepared by the following steps: 80 parts of waterborne epoxy resin, 10 parts of compound flame retardant, and 10 parts of deionized water are mixed and stirred evenly to obtain a prefabricated coating, and then 40 parts of curing agent are added and stirred evenly to obtain Comparative Coating 1; the compound flame retardant consists of unmodified Al(OH)3, Mg(OH)2 and organically flame-retardant modified zinc borate, and the mass ratio of the three is 4:4:1.

[0065] The organically flame-retardant modified zinc borate is prepared by the following steps:

[0066] Disperse 1 g of zinc borate in 100 mL of deionized water, after ultrasonic dispersion, add tris(hydroxymethyl)aminomethane hydrochloride to adjust the pH of the solution to 8, then add 0.05 g of dopamine hydrochloride, and stir the reaction solution at 20 o After stirring and reacting at °C for 4 h, carry out suction filtration, wash with deionized water for multiple times, and dry to obtain poly-dopamine-coated zinc borate.

[0067] The coatings obtained in Examples 1-3 and Comparative Examples 1-5 were evenly brushed on the surface of a steel sheet (sandblasted to Sa2 level), the average thickness of the coating was kept at about 1.5 mm, and it was cured at room temperature for one week to obtain a specimen coating. The morphology and the ultimate flame resistance time of each coating preparation process are listed in Table 1.

[0068] Table 1 Morphology and ultimate fire resistance time of the coatings obtained in Examples 1-3 and Comparative Examples 1-5 during the preparation process

[0069] Method Morphology during the coating preparation process Ultimate flame-retardant time Example 1 Smooth, delicate, without particle attachment 37 min Example 2 Smooth, delicate, without particle attachment 47 min Example 3 Smooth, delicate, without particle attachment 52 min Comparative Example 1 Smooth, delicate, without particle attachment 22 min Comparative Example 2 With a small amount of particle attachment 23 min Comparative Example 3 With a small amount of particle attachment 25 min Comparative Example 4 Smooth, delicate, without particle attachment 30 min Comparative Example 5 With a small amount of particle attachment 27 min

[0070] By comparing the results of the examples and the comparative examples, it can be clearly seen that the multi-component composite flame retardant prepared by the present invention exhibits significant advantages. This flame retardant not only effectively composits each component together through strong chemical bonds, but also fully exerts the high-efficiency flame retardant synergistic effect among flame retardant components such as Al(OH)3, Mg(OH)2, triazine structures, polydopamine, halogens, and zinc borate. This synergistic effect promotes the formation of a denser carbon layer. In addition, the surface of the composite flame retardant is rich in a large number of active functional groups, which can form strong interactions with the resin matrix, thus significantly improving the compatibility between the flame retardant and the matrix. Therefore, the coatings prepared by the present invention exhibit excellent flame retardant properties. In contrast, in Comparative Example 2, unmodified Al(OH)3 and Mg(OH)2 were used as the compounded flame retardant. It can be seen that even with a small amount added, the improvement of the flame retardant performance of the coating is extremely limited. In Comparative Example 3, magnesium silicate was further added. However, due to the weak interaction among unmodified Al(OH)3, Mg(OH)2, and magnesium silicate and the easy occurrence of agglomeration, the improvement of the flame retardant performance of the resulting coating is not obvious. In Comparative Examples 4 and 5, effective composite formation among Al(OH)3, Mg(OH)2, and zinc borate could not be achieved, so the synergistic flame retardant effect could not be fully exerted, and the flame retardant performance of the coatings was naturally inferior to that of the coatings in the examples. In summary, the multi-component composite flame retardant of the present invention shows obvious advantages in improving the flame retardant performance of coatings.

[0071] The present invention is not limited to the above specific embodiments. For those of ordinary skill in the art, starting from the above conceptions, without creative labor, all kinds of transformations made fall within the protection scope of the present invention.

Claims

1. A multi-component synergistic flame retardant modified coating, characterized in that: The multi-component synergistic flame retardant modified coating comprises the following components by weight: 80-100 parts of waterborne epoxy resin, 10-20 parts of multi-component composite flame retardant, 40-50 parts of curing agent, and 10-15 parts of deionized water; the multi-component composite flame retardant is composed of organic flame retardant modified Al(OH)3, organic flame retardant modified Mg(OH)2 and organic flame retardant modified zinc borate; The organic flame retardant modified Al(OH)3 and the organic flame retardant modified Mg(OH)2 are prepared by the following steps: Epoxysilane KH-560 was added to a mixed solution of water and methanol, and an organic acid was added to adjust the pH value of the solution to 3.85-4.

2. Finally, inorganic nanoparticles Al(OH)3 or Mg(OH)2 were added and dispersed evenly by ultrasonication. The reaction solution was heated to 50-80°C. o After stirring and reacting for 6 to 10 hours at 40 °C, the mixture was filtered, washed with deionized water for several times, and dried to obtain epoxy-modified Al(OH)3 or Mg(OH)2) nanoparticles; The epoxy-modified nanoparticles prepared in step a are added to dimethyl sulfoxide, and 2-amino-4,6-dichloro-S-triazine is added, the mixture is ultrasonically dispersed uniformly, and then heated at 80 to 120 o After stirring and reacting for 6 to 10 hours at 400 °C, the mixture was filtered, washed with deionized water for several times, and dried to obtain organic flame retardant modified Al(OH)3 or Mg(OH)2 nanoparticles; The organic flame retardant modified zinc borate is prepared by the following steps: dispersing zinc borate in deionized water, adding tris(hydroxymethyl)aminomethane hydrochloride after ultrasonic dispersion, adjusting the pH value of the solution to 8-9, then adding dopamine hydrochloride, and heating the reaction solution at 20-40°C. o C, stirred for reaction for 2-4 hours, filtered, washed with deionized water for several times, and dried to obtain polydopamine-modified zinc borate.

2. The multi-component synergistic flame retardant modified coating according to claim 1, characterized in that: The dosage of KH-560, the mixed solution of water and methanol, and the inorganic nanoparticles in step a is as follows: for every 0.2 to 0.5 g of KH-560, add 200 to 300 mL of a mixed solution of water and methanol with a volume ratio of 2 to 4:1, and add 6 to 10 g of inorganic nanoparticles.

3. The multi-component synergistic flame retardant modified coating according to claim 1, characterized in that: The dosage of the epoxy-modified nanoparticles, dimethyl sulfoxide, and 2-amino-4,6-dichloro-S-triazine in step b is as follows: 100-200 mL of dimethyl sulfoxide and 0.6-1 g of 2-amino-4,6-dichloro-S-triazine are added for every 1-1.5 g of epoxy-modified nanoparticles.

4. The multi-functional flame retardant modified coating according to claim 1, characterized in that: When preparing the organic flame retardant modified zinc borate, the dosage of zinc borate, deionized water and dopamine hydrochloride is as follows: 1-2g of zinc borate is dispersed in 100-200ml of deionized water, and 0.05-0.1g of dopamine hydrochloride is added.

5. The multi-component synergistic flame retardant modified coating according to claim 1, characterized in that: The multi-component composite flame retardant is prepared by the following steps: dispersing organic flame retardant modified Al(OH)3 and organic flame retardant modified Mg(OH)2 nanoparticles in ethanol, ultrasonically uniformly obtaining a dispersion with a mass fraction of 10-20%, then ultrasonically dispersing organic flame retardant modified zinc borate in the prepared dispersion, stirring for 1-3 hours, filtering, retaining solids, washing, and drying to obtain a multi-component composite flame retardant composed of Al(OH)3, Mg(OH)2, organic flame retardant modifier, and zinc borate.

6. The multi-component synergistic flame retardant modified coating according to claim 5, characterized in that: The mass ratio of organic flame retardant modified Al(OH)3, organic flame retardant modified Mg(OH)2 and organic flame retardant modified zinc borate in the multi-component composite flame retardant is 4-7:4-7:

1.

7. A method for preparing the multi-component synergistic flame retardant modified coating according to claim 1, characterized in that: The preparation method comprises the following preparation steps: A. Mixing waterborne epoxy resin, multi-component composite flame retardant and deionized water to obtain a prefabricated coating; B. Mixing the prefabricated coating and the curing agent to obtain a multi-component synergistic flame retardant modified coating.