A fire-retardant and high-temperature resistant resin coating and its preparation method and application

Abstract

The present invention discloses a fireproof and high-temperature resistant resin coating and its preparation method and application, which belong to the field of surface coating technology. The fireproof and high-temperature resistant resin coating of the present invention includes epoxy resin, thermosetting phenolic resin, yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine and methylhexahydrophthalic anhydride. The present invention improves the high toughness, high adhesion and thermal insulation of the fireproof and high-temperature resistant coating by modifying epoxy resin with phenolic resin, improving the uniformity of the coating by the condensation product of 3-aminopropyltrimethoxysilane and polydimethylsiloxane, preparing polyethylenediamine phosphate and forming a catalytic coating system of reaction byproducts. The coating not only has the advantages of high temperature resistance of phenolic resin and toughness and adhesion of epoxy resin, but also shows strong mechanical properties, and has broad application prospects in the fields of thermal insulation, heat insulation and high-temperature protection.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface coatings, and in particular relates to a fireproof and high-temperature resistant resin coating and a preparation method and application thereof. Background Art

[0002] Epoxy resins, with their advantages of high hardness and good plasticity, are highly applicable in the field of anti-corrosion coatings. However, due to the presence of polar groups such as hydroxyl groups, most epoxy resins have poor thermal stability and are not resistant to high temperatures. In the early stages of epoxy resin degradation, the main chain of the molecule degrades, and the pyrolysis gas phase is primarily composed of water and complex compounds containing methane, carbonyl groups, and benzene rings. As the temperature rises, small molecules (carbon monoxide, carbon dioxide, methanol, etc.) appear in gas-phase infrared spectroscopy. In the high-temperature pyrolysis gas of epoxy resin, carbon monoxide and methanol are both flammable gases. With an oxygen index of only 19.8, epoxy resin is highly flammable. In fire accidents, epoxy resin is often the most flammable component of the composite material, and after a fire, it continues to burn and emits significant amounts of smoke. Improving the fire resistance of epoxy resin at the source and reducing the amount of smoke and toxic gases released during combustion are urgent issues that the epoxy resin industry needs to address.

[0003] Phenolic resins have the advantages of low thermal conductivity, high carbon residue rate and good thermal insulation. Since the 1960s, they have been used as high-temperature resistant materials in aerospace equipment such as missiles, aircraft, and hypersonic aircraft. They are also the main matrix resin currently used in resin-based thermal ablation-resistant materials. However, they have problems such as poor toughness and poor adhesion.

[0004] Mixing phenolic resin and epoxy resin and then adding ammonium polyphosphate can improve the material's flame retardancy. This is primarily due to its relatively low fire resistance at high temperatures, which can inhibit or delay the material's combustion process through exothermic and endothermic reactions. Ammonium polyphosphate may decompose at high temperatures to produce gases and form a foamy substance. This foamy structure helps insulate and slow the spread of flames. Although ammonium polyphosphate has a certain flame retardant effect, its relatively low fire resistance under high temperature conditions may not provide long-term fire protection.

[0005] Currently, existing coating materials may lose their fire resistance or high-temperature resistance under certain circumstances, or the coating may peel off during use. In addition, existing coating preparation methods may require complex processes and expensive equipment, limiting their application in large-scale production. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a fire-retardant and high-temperature resistant resin coating and a preparation method and application thereof.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A fireproof and high-temperature resistant resin coating comprises epoxy resin, thermosetting phenolic resin, yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine and methylhexahydrophthalic anhydride.

[0009] As a preferred embodiment of the present invention, the mass ratio of the epoxy resin, thermosetting phenolic resin, yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine and methylhexahydrophthalic anhydride is 8:5:2-6:2.4-7.2:2-6:1.7-5:6.

[0010] As a preferred embodiment of the present invention, the fireproof and high temperature resistant resin coating further includes an organosilicon defoamer, and the mass of the organosilicon defoamer is 1‰ to 3‰ of the total mass of the fireproof and high temperature resistant resin coating.

[0011] A method for preparing a fire-retardant and high-temperature resistant resin coating comprises the following steps:

[0012] (1) mixing an epoxy resin and a thermosetting phenolic resin, then adding yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine, and an organosilicon defoamer, stirring and heating to obtain a mixed solution;

[0013] (2) Methylhexahydrophthalic anhydride is added to the mixed solution, and the mixture is stirred and vacuumed to obtain a fire-retardant and high-temperature resistant resin coating.

[0014] As a preferred embodiment of the present invention, the epoxy resin and the thermosetting phenolic resin are mixed by stirring at 80° C. for 25 minutes.

[0015] As a preferred embodiment of the present invention, in step (1), the stirring and heating temperature is 85° C., and the stirring speed is 400-500 r / min.

[0016] As a preferred embodiment of the present invention, in the step (2), the stirring temperature is 75° C. and the stirring speed is 600-700 r / min.

[0017] As a preferred embodiment of the present invention, a fireproof and high-temperature resistant resin coating is applied to the surface of a substrate to form a fireproof and high-temperature resistant resin coating, and the substrate is carbon fiber, aluminum alloy or cast iron. Specifically, in order to improve the bonding strength between the coating and the substrate surface, the substrate surface must be cleaned and roughened before spraying. First, a mechanical method is used to remove oil and oxide film from the substrate surface, and sandblasting is used to roughen the substrate surface, remove moisture from the surface, and reduce the relative thermal expansion of the substrate and the coating. The fireproof and high-temperature resistant resin coating is then evenly applied to the substrate surface, cured at 150°C for 2 hours, and then cooled in the furnace to obtain a coating.

[0018] As a preferred embodiment of the present invention, the thickness of the fire-proof and high-temperature resistant resin coating is 5-15 mm.

[0019] The fireproof and high-temperature resistant resin coating of the present invention has a thermal conductivity of 0.035 to 0.045 W / K at 1000° C. and has good heat insulation capability.

[0020] Principle of the present invention:

[0021] The present invention adds yttria-stabilized zirconia. Yttria doping inhibits the transformation of the tetragonal to monoclinic phase of zirconia, improving its thermal stability. Yttria-stabilized zirconia's low thermal conductivity and thermal expansion coefficient, high mechanical strength, and high-temperature stability, combined with its unique microcracks and phase transformation toughening mechanism, result in coatings with excellent thermal shock resistance and mechanical properties.

[0022] The present invention forms polyethylenediamine phosphate by a condensation reaction between ethylenediamine and ammonium polyphosphate. The polyethylenediamine phosphate molecule contains ethylenediamine groups and phosphate ions, further improving the material's fire resistance. In contrast, ammonium polyphosphate has relatively low fire resistance and easily decomposes at high temperatures to produce gas, forming a foamy substance that loses its structural integrity. Therefore, in applications requiring higher fire resistance, polyethylenediamine phosphate has better thermal stability and mechanical properties and can maintain its structural integrity under high-temperature environments. Furthermore, the condensation reaction between ethylenediamine and ammonium polyphosphate to form polyethylenediamine phosphate also generates ammonia water, which accelerates the reaction rate of the phenolic resin and epoxy resin and promotes the reaction between 3-aminopropyltrimethoxysilane and polydimethylsiloxane. The ammonia water can promote the chemical bonding between the amine groups in the resin system and the substrate surface, improving the adhesion and durability of the coating.

[0023] The present invention adds polydimethylsiloxane to form a dispersion layer on the powder surface, which helps to effectively disperse the powder and prevent its agglomeration in the resin matrix, thereby improving the uniformity and performance stability of the composite material. The molecular structure of polydimethylsiloxane enables it to reduce the interfacial energy between yttria-stabilized zirconia, ammonium polyphosphate and the resin matrix, which helps to enhance the compatibility between the two, reduce interfacial stress concentration, and improve the mechanical properties of the composite material. In addition, the present invention forms new silicon-oxygen bonds and amino bonds through the nucleophilic substitution reaction between the amino group of 3-aminopropyltrimethoxysilane and the hydroxyl group on the surface of the polydimethylsiloxane particles, thereby improving the dispersion performance of the filler particles and increasing their compatibility with the coating matrix.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention improves the uniformity of the coating by modifying the epoxy resin with phenolic resin, the condensation product of 3-aminopropyltrimethoxysilane and polydimethylsiloxane, and the reaction products and by-products of the condensation reaction of ethylenediamine and ammonium polyphosphate promote the formation of the coating system to improve the high toughness, high adhesion and thermal insulation of the fire-retardant and high-temperature resistant coating. The coating not only has the advantages of the high-temperature resistance of phenolic resin and the toughness and adhesion of epoxy resin, but also exhibits strong mechanical properties, and has broad application prospects in the fields of thermal insulation, heat insulation and high-temperature protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flow chart of a method for preparing a fire-retardant and high-temperature resistant resin coating.

[0026] Figure 2 This is the SEM image of the coating prepared in Example 1.

[0027] Figure 3 This is the SEM image of the coating prepared in Comparative Example 1. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0029] Examples 1-5 and Comparative Examples 1-8

[0030] A method for preparing a fire-retardant and high-temperature resistant resin coating comprises the following steps:

[0031] (1) According to the addition amount of each substance in Table 1 and Table 2, epoxy resin and thermosetting phenolic resin were stirred and mixed at a constant temperature of 80°C for 25 minutes, and then yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine, and silicone defoamer were added, and the mixture was stirred and heated at 85°C and a speed of 400 r / min to obtain a mixed solution;

[0032] (2) Methylhexahydrophthalic anhydride was added to the mixed solution at 75° C., and the mixture was stirred (stirring speed was 600 r / min) and vacuumed to obtain a fire-retardant and high-temperature resistant resin coating.

[0033] The fire-retardant and high-temperature-resistant resin coatings prepared in the Examples and Comparative Examples were applied to the carbon fiber surface. Prior to spraying, the substrate surface was mechanically degreased and deoxidized. Sandblasting was used to roughen the substrate surface, remove surface moisture, and reduce the relative thermal expansion between the substrate and the coating. The fire-retardant and high-temperature-resistant resin coating was then evenly applied to the substrate surface, cured at 150°C for 2 hours, and then cooled in the furnace to produce a coating with a thickness of 10 mm.

[0034] The comprehensive performance test of the fire-retardant and high-temperature resistant resin coating is carried out, and the results are shown in Tables 1 and 2.

[0035] Table 1 Chemical composition and parameters of the examples

[0036]

[0037] Table 2 Chemical composition and parameters of comparative examples

[0038]

[0039]

[0040] according to Figure 2 and 3 It can be seen that the coatings prepared in Examples 1-5 have no obvious cracks, holes or other defects, and the surface is smooth and uniform, and the thermal insulation performance of the coatings is good. Figure 3 The coating prepared in Comparative Example 1 shows raised spots on its surface, primarily due to uneven distribution of the powder within the resin, with some powder floating on the resin surface. These raised spots can cause heat to accumulate in localized areas, forming hot spots. These hot spots raise the coating's temperature, increasing thermal conductivity and heat loss, thereby reducing the overall fireproofing and heat insulation effectiveness.

[0041] It can be seen from Examples 1-5 and Comparative Examples 1-8 that the fire-resistant and high-temperature resistant resin coating of the present invention has good high-temperature resistance and mechanical properties.

[0042] According to Example 1 and Comparative Examples 1, 2, and 8, the present invention forms new silicon-oxygen bonds and amino bonds through a nucleophilic substitution reaction between the amino group of 3-aminopropyltrimethoxysilane and the hydroxyl group on the surface of the polydimethylsiloxane particles, thereby improving the dispersion performance of the filler particles and increasing their compatibility with the coating matrix, thereby improving the fire resistance and density of the coating.

[0043] According to Example 1 and Comparative Example 3, by adjusting the specific gravity of the epoxy resin, the coating can simultaneously have the effects of high temperature resistance, high strength and rigidity, and reduced smoke generation rate.

[0044] According to Example 1 and Comparative Examples 4-5, ethylenediamine and ammonium polyphosphate are added to the coating, and a condensation reaction occurs between ethylenediamine and ammonium polyphosphate to form polyethylenediamine phosphate and ammonia, thereby further improving the fire resistance, density, strength of the material, and adhesion and durability of the coating.

[0045] As shown in Example 1 and Comparative Examples 6-7, pure zirconium oxide and yttrium oxide have relatively high coefficients of thermal expansion, making them susceptible to cracking caused by thermal stress during rapid heating or cooling. Due to the addition of yttrium ions, yttria-stabilized zirconia possesses higher mechanical strength, making it more suitable for engineering applications requiring high-strength materials. However, pure zirconium oxide and yttrium oxide may exhibit certain mechanical disadvantages.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A fire-retardant and high-temperature resistant resin coating, characterized in that: include: Epoxy resin, thermosetting phenolic resin, yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine, methylhexahydrophthalic anhydride, and silicone defoamer; The mass ratio of the epoxy resin, thermosetting phenolic resin, yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine and methylhexahydrophthalic anhydride is 8:5:6:5:6:6:5:6, 8:5:6:3:3.6:6:5:6, 8:5:6:6:7.2:6:5:6, 8:5:6:4:4.8:2:1.7:6 or 8:5:6:2:2.4:2:1.7:6; the mass of the organosilicon defoamer is 1‰ to 3‰ of the total mass of the fire-retardant and high-temperature resistant resin coating; The preparation method of the fire-retardant and high-temperature resistant resin coating comprises the following steps: (1) Epoxy resin and thermosetting phenolic resin are mixed, and then yttria-stabilized zirconia, polydimethylsiloxane, 3-aminopropyltrimethoxysilane, ammonium polyphosphate, ethylenediamine, and silicone defoamer are added, and the mixture is stirred and heated to obtain a mixed solution; (2) Methylhexahydrophthalic anhydride is added to the mixed solution, and after stirring and vacuuming, a fire-retardant and high-temperature resistant resin coating is obtained.

2. The fireproof and high temperature resistant resin coating according to claim 1, characterized in that: The epoxy resin and the thermosetting phenolic resin were mixed by stirring at 80° C. for 25 minutes.

3. The fireproof and high temperature resistant resin coating according to claim 1, characterized in that: In the step (1), the stirring and heating temperature is 85° C., and the stirring speed is 400-500 r / min.

4. The fireproof and high temperature resistant resin coating according to claim 1, characterized in that: In the step (2), the stirring temperature is 75° C. and the stirring speed is 600-700 r / min.

5. A fireproof and high temperature resistant resin coating, characterized in that: The fireproof and high-temperature resistant resin coating according to claim 1 is applied on the surface of a substrate and cured to form a fireproof and high-temperature resistant resin coating, wherein the substrate is carbon fiber, aluminum alloy or cast iron.

6. The fireproof and high temperature resistant resin coating according to claim 5, characterized in that: The thickness of the coating formed on the substrate surface is 5-15 mm.

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