A highly waterproof and corrosion-resistant fireproof coating and its preparation method

Abstract

The present invention relates to a high waterproof and corrosion-resistant fireproof coating and a preparation method thereof, belonging to the technical field of fireproof coatings. By mass parts, it includes 20-25 parts of waterborne epoxy resin, 10-15 parts of pure acrylic emulsion, 5-10 parts of polyurethane emulsion, 15-20 parts of organosilicon-modified ammonium polyphosphate, 8-10 parts of dipentaerythritol, 6-8 parts of melamine, 3-5 parts of graphene oxide-polyacrylic acid-nano silica composite, 8-12 parts of pigment and filler, 4-6 parts of zinc phosphate, 4-6 parts of additives and 8-10 parts of water. Through the optimization of the formula, at high temperature, the coating can form an expanded carbon layer, effectively isolate heat and oxygen, delay or prevent the spread of fire, and achieve the effects of high waterproofness and corrosion resistance on the basis of the high fireproof performance of the fireproof coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of fireproof coatings, and particularly relates to a fireproof coating with high water resistance and corrosion resistance and a preparation method thereof. Background Art

[0002] Steel structure fireproof coatings are coatings specifically used to improve the fire resistance of steel structures. Although steel itself does not burn, its mechanical properties (such as yield point, tensile strength, and elastic modulus) will decrease sharply under high-temperature environments. To prevent steel structures from losing their load-bearing capacity in fires, steel structure fireproof coatings are widely used in buildings and other engineering structures. These coatings can form a fire-resistant and heat-insulating protective layer during a fire, thereby increasing the fire resistance limit of steel structures.

[0003] Steel structure fireproof coatings mainly consist of the following components:

[0004] 1. Film-forming substance: It not only ensures that the coating has various usage functions under normal conditions but also has flame retardancy and excellent expansion and foaming properties under flame burning or high-temperature conditions.

[0005] 2. Catalyst: A substance that can decompose phosphoric acid under certain conditions. The decomposed acid dehydrates the polyol, thereby forming a charred layer with a non-flammable three-dimensional spatial structure.

[0006] 3. Carbonizing agent: It is the material basis for the coating to form a non-flammable three-dimensional spatial structure of a foam carbonized layer at high temperatures and plays a skeletal role in the foam carbonized layer.

[0007] 4. Foaming agent: Only under the action of the foaming agent can an expansion layer be generated under high-temperature flames. The foaming agent decomposes when encountering fire and releases non-flammable gases such as ammonia, water, carbon dioxide, and hydrogen halide, causing the coating to foam and expand when reaching the softening point, forming a sponge-like structure.

[0008] Although existing steel structure fireproof coatings have advantages such as good fireproof performance, strong durability, and convenient construction, they still need to be improved in terms of water resistance and corrosion resistance. Summary of the Invention

[0009] The present invention aims to provide a fireproof coating with high water resistance and corrosion resistance and a preparation method thereof. Through the optimization of the formula, at high temperatures, the coating can form an expanded carbon layer, effectively isolating heat and oxygen, delaying or preventing the spread of flames, and achieving high water resistance and corrosion resistance on the basis of the high fireproof performance of the fireproof coating.

[0010] The technical solution adopted by the present invention to achieve its purpose:

[0011] A high waterproof and corrosion-resistant fireproof coating, by mass parts, comprises 20-25 parts of waterborne epoxy resin, 10-15 parts of pure acrylic emulsion, 5-10 parts of polyurethane emulsion, 15-20 parts of organosilicon-modified ammonium polyphosphate, 8-10 parts of dipentaerythritol, 6-8 parts of melamine, 3-5 parts of graphene oxide-polyacrylic acid-nano silica composite, 8-12 parts of pigment and filler, 4-6 parts of zinc phosphate, 4-6 parts of additives and 8-10 parts of water.

[0012] Preferably, the graphene oxide-polyacrylic acid-nano silica composite is prepared by the following method:

[0013] S1. Disperse graphene oxide in deionized water, and perform ultrasonic dispersion to obtain a graphene oxide dispersion liquid; add a silane coupling agent thereto, and perform stirring reaction at 60-70 °C for 4-6 h to obtain silane coupling agent-treated graphene oxide;

[0014] S2. Disperse the silane coupling agent-treated graphene oxide in deionized water, add a polyacrylic acid solution with a mass concentration of 5-7%, and perform stirring reaction at 60-70 °C for 6-8 h to obtain a graphene oxide-polyacrylic acid composite;

[0015] S3. Disperse nano silica in deionized water, and perform ultrasonic dispersion to obtain a nano silica dispersion liquid; disperse the graphene oxide-polyacrylic acid composite in deionized water, and perform ultrasonic dispersion to obtain a graphene oxide-polyacrylic acid composite dispersion liquid, mix it with the nano silica dispersion liquid, perform stirring reaction at 60-70 °C for 4-6 h, perform centrifugal separation, wash with deionized water, and dry to obtain a graphene oxide-polyacrylic acid-nano silica composite.

[0016] Preferably, the time of ultrasonic dispersion is 1-2 h.

[0017] Preferably, the dosage of the silane coupling agent is 1-2% of the mass of graphene oxide.

[0018] Preferably, the pigment and filler are selected from one or more of silicate, aluminum hydroxide, magnesium hydroxide, aluminum oxide, zinc borate, expanded graphite, and nano clay.

[0019] Preferably, the additives include one or more of a thickener, a leveling agent, a dispersant, and a toughening agent.

[0020] A preparation method of a high waterproof and corrosion-resistant fireproof coating comprises the following steps:

[0021] A. Premixing: Add waterborne epoxy resin, pure acrylic emulsion, polyurethane emulsion and water into a reaction kettle, and stir evenly;

[0022] B. Filler dispersion: Add silicone-modified ammonium polyphosphate, dipentaerythritol, and melamine into the premixed solution and stir at high speed; then add graphene oxide-polyacrylic acid-nano-silica composite, zinc phosphate, pigments and fillers, and additives into the premixed solution and stir at high speed to obtain the coating.

[0023] C. Filtration and packaging: Filter the prepared coating to remove impurities, and then package and store it.

[0024] Preferably, the stirring rate for high-speed stirring is 800 - 2000 r / min, and the stirring time is 1 - 3 h.

[0025] The beneficial effects of the present invention are as follows:

[0026] By using waterborne epoxy resin, pure acrylic emulsion, and polyurethane emulsion as film-forming substances, the present invention not only has good film-forming ability, but also can match the decomposition temperature of the P-N-C system. It can cooperate with the intumescent flame retardant system at high temperature or in case of fire to form a porous intumescent layer, preventing the rapid temperature rise of the steel structure. The polyurethane emulsion in the film-forming substances can increase the toughness of the coating, preventing the phenomenon of "thermal brittleness and cold stickiness". At the same time, the addition of polyurethane emulsion and waterborne epoxy resin improves the water resistance of the coating. The cured film forms a dense surface, which can effectively block the penetration of water, significantly improving the waterproof performance of the coating. The waterborne epoxy resin in the film-forming substances can also improve the adhesion between the coating and the steel plate, improving the strength of the carbon layer. The combined use of the three effectively encapsulates the incombustible gases released by the flame retardant system, increasing the carbon layer expansion ratio.

[0027] Silicone-modified ammonium polyphosphate, dipentaerythritol, and melamine constitute the flame retardant system. Silicone-modified ammonium polyphosphate, as the acid source, decomposes at high temperature to release phosphoric acid, promoting the dehydration and carbonization of the carbon source (dipentaerythritol) to form a carbon layer. Melamine, as the gas source, decomposes at high temperature to release gases (such as ammonia), causing the carbon layer to expand and form a porous and dense heat insulation layer, thus achieving the effect of flame retardancy and fire prevention. Among them, ammonium polyphosphate is modified with silicone to reduce its hygroscopicity, providing a basis for the high waterproofness of the fireproof coating.

[0028] The graphene oxide-polyacrylic acid-nano-silica composite contains graphene oxide and nano-silica, which has hydrophobicity and can enhance the waterproof performance of the coating film. At the same time, this composite fills the micropores in the coating film, improving the denseness of the coating film and preventing the penetration of water and corrosive ions into the coating, thereby enhancing the waterproof effect and corrosion resistance effect. On the other hand, the graphene oxide-polyacrylic acid-nano-silica composite plays a strengthening role in the carbon layer, improving the mechanical strength and heat insulation performance of the carbon layer, so it can further enhance the fireproof performance and durability of the coating.

[0029] Pigments and fillers are used to adjust the color and hiding power of the coating, and may also have a certain auxiliary effect on the fire resistance performance. Additives improve the leveling, dispersibility and stability of the coating, etc., ensuring the construction performance and film quality.

[0030] Zinc phosphate is added as an anti-rust pigment, and its function is to improve the corrosion resistance of the coating. Specific embodiments

[0031] All raw materials used in the present invention are purchased from the market, and those not described in the present invention are all prior arts. The present invention will be described in detail below in combination with specific examples and performance tests.

[0032] Example 1

[0033] Prepare graphene oxide - polyacrylic acid - nano - silica composite:

[0034] The mass ratio of graphene oxide, nano - silica and polyacrylic acid is 1:2:3, and the specific preparation process is as follows:

[0035] S1. Disperse graphene oxide in deionized water, and ultrasonically disperse for 1 h to obtain a graphene oxide dispersion; add 2% of the silane coupling agent KH - 550 based on the mass of graphene oxide to it, and stir and react at 60 °C for 4 h. After the reaction is completed, centrifuge and separate, and wash with deionized water to remove the unreacted silane coupling agent to obtain silane coupling agent - treated graphene oxide;

[0036] S2. Disperse the silane coupling agent - treated graphene oxide in deionized water, add a polyacrylic acid solution with a mass concentration of 6%, and stir and react at 60 °C for 8 h. After the reaction is completed, centrifuge and separate, and wash with deionized water to obtain a graphene oxide - polyacrylic acid composite;

[0037] S3. Disperse nano - silica in deionized water, and ultrasonically disperse for 1 h to obtain a nano - silica dispersion; disperse the graphene oxide - polyacrylic acid composite in deionized water, ultrasonically disperse to obtain a graphene oxide - polyacrylic acid composite dispersion, mix it with the nano - silica dispersion, stir and react at 60 °C for 4 h, centrifuge and separate, wash with deionized water, and dry to obtain a graphene oxide - polyacrylic acid - nano - silica composite.

[0038] Example 2

[0039] A highly water - proof and corrosion - resistant fire - retardant coating, by mass fraction, comprises 20 parts of water - borne epoxy resin, 13 parts of pure acrylic emulsion, 8 parts of polyurethane emulsion, 15 parts of organosilicon - modified ammonium polyphosphate, 8 parts of dipentaerythritol, 6 parts of melamine, 3 parts of graphene oxide - polyacrylic acid - nano - silica composite, 5 parts of potassium silicate, 2 parts of magnesium hydroxide, 1 part of zinc borate, 4 parts of zinc phosphate, 1 part of leveling agent, 2 parts of dispersant, 1 part of toughening agent and 8 parts of water.

[0040] Example 3

[0041] A highly water - proof and corrosion - resistant fire - retardant coating, by mass fraction, comprises 25 parts of water - borne epoxy resin, 10 parts of pure acrylic emulsion, 10 parts of polyurethane emulsion, 20 parts of organosilicon - modified ammonium polyphosphate, 10 parts of dipentaerythritol, 8 parts of melamine, 5 parts of graphene oxide - polyacrylic acid - nano - silica composite, 6 parts of potassium silicate, 3 parts of aluminum hydroxide, 1 part of zinc borate, 6 parts of zinc phosphate, 2 parts of leveling agent, 2 parts of dispersant, 1 part of toughening agent and 10 parts of water.

[0042] Example 4

[0043] A highly water - proof and corrosion - resistant fire - retardant coating, by mass fraction, comprises 23 parts of water - borne epoxy resin, 15 parts of pure acrylic emulsion, 5 parts of polyurethane emulsion, 17 parts of organosilicon - modified ammonium polyphosphate, 9 parts of dipentaerythritol, 7 parts of melamine, 4 parts of graphene oxide - polyacrylic acid - nano - silica composite, 6 parts of potassium silicate, 4 parts of magnesium hydroxide, 2 parts of zinc borate, 5 parts of zinc phosphate, 2 parts of leveling agent, 2 parts of dispersant, 2 parts of toughening agent and 9 parts of water.

[0044] Example 5

[0045] The highly water - proof and corrosion - resistant fire - retardant coatings in the above Examples 2 - 3 are all prepared by the following method, including the following steps:

[0046] A. Premixing: Add water - borne epoxy resin, pure acrylic emulsion, polyurethane emulsion and water into a reaction kettle and stir evenly.

[0047] B. Filler dispersion: Add organosilicon - modified ammonium polyphosphate, dipentaerythritol, melamine into the premixed solution and stir at a high speed of 100 r / min for 1 h; then add graphene oxide - polyacrylic acid - nano - silica composite, zinc phosphate, pigment fillers and additives into the premixed solution and stir at a high speed of 1500 r / min for 3 h to obtain the coating.

[0048] C. Filtration and packaging: Filter the prepared coating to remove impurities and then package and store it.

[0049] Comparative Example 1

[0050] A highly waterproof and corrosion-resistant fireproof coating comprises, by weight, 20 parts of waterborne epoxy resin, 13 parts of pure acrylic emulsion, 8 parts of polyurethane emulsion, 15 parts of organosilicon-modified ammonium polyphosphate, 3 parts of graphene oxide, 8 parts of dipentaerythritol, 6 parts of melamine, 5 parts of potassium silicate, 2 parts of magnesium hydroxide, 1 part of zinc borate, 4 parts of zinc phosphate, 1 part of leveling agent, 2 parts of dispersant, 1 part of toughening agent and 8 parts of water. The preparation method is the same as that of Example 5.

[0051] Comparative Example 2

[0052] A highly waterproof and corrosion-resistant fireproof coating comprises, by weight, 20 parts of waterborne epoxy resin, 13 parts of pure acrylic emulsion, 15 parts of organosilicon-modified ammonium polyphosphate, 8 parts of dipentaerythritol, 6 parts of melamine, 3 parts of nano-silicon dioxide, 5 parts of potassium silicate, 2 parts of magnesium hydroxide, 1 part of zinc borate, 4 parts of zinc phosphate, 1 part of leveling agent, 2 parts of dispersant, 1 part of toughening agent and 8 parts of water. The preparation method is the same as that of Example 5.

[0053] Comparative Example 3

[0054] A highly waterproof and corrosion-resistant fireproof coating comprises, by weight, 20 parts of waterborne epoxy resin, 13 parts of pure acrylic emulsion, 15 parts of organosilicon-modified ammonium polyphosphate, 8 parts of dipentaerythritol, 6 parts of melamine, 2 parts of nano-silicon dioxide, 1 part of graphene oxide, 5 parts of potassium silicate, 2 parts of magnesium hydroxide, 1 part of zinc borate, 4 parts of zinc phosphate, 1 part of leveling agent, 2 parts of dispersant, 1 part of toughening agent and 8 parts of water. The preparation method is the same as that of Example 5.

[0055] Comparative Example 4

[0056] A highly waterproof and corrosion-resistant fireproof coating comprises, by weight, 20 parts of waterborne epoxy resin, 13 parts of pure acrylic emulsion, 15 parts of organosilicon-modified ammonium polyphosphate, 8 parts of dipentaerythritol, 6 parts of melamine, 3 parts of graphene oxide-polyacrylic acid-nano silicon dioxide composite, 5 parts of potassium silicate, 2 parts of magnesium hydroxide, 1 part of zinc borate, 4 parts of zinc phosphate, 1 part of leveling agent, 2 parts of dispersant, 1 part of toughening agent and 16 parts of water. The preparation method is the same as that of Example 5.

[0057] Test Example 1

[0058] The basic performance test of outdoor steel structure fire retardant coating refers to GB14907-2018 "Steel Structure Fire Retardant Coating", and the results are shown in Table 1.

[0059] Table 1

[0060]

[0061] Test Example 2

[0062] Water resistance test: The coating film sample was immersed in water for 5 days, and the changes on the surface and edge of the coating film were observed. The results are shown in Table 2.

[0063] Table 2

[0064] Treatment Coating change Example 2 No foaming, no peeling, no discoloration Example 3 No foaming, no peeling, no discoloration Example 4 No foaming, no peeling, no discoloration Comparative Example 1 Obvious foaming, no peeling, no discoloration Comparative Example 2 Obvious foaming, no peeling, no discoloration Comparative Example 3 Slight foaming, no peeling, no discoloration Comparative Example 4 Foaming, partial peeling, no discoloration

[0065] Test Example 3

[0066] Fire resistance performance detection, and the results are shown in Table 3.

[0067] Table 3

[0068]

[0069] In summary, the high waterproof, corrosion-resistant and fireproof coating of the present invention has excellent fire resistance performance, and also has high water resistance and corrosion resistance. Its physical and chemical properties meet the national standards and can achieve an effective fire protection effect.

Claims

1. A fireproof coating with high waterproof and corrosion resistance, characterized in that, By mass parts, it includes 20 - 25 parts of waterborne epoxy resin, 10 - 15 parts of pure acrylic emulsion, 5 - 10 parts of polyurethane emulsion, 15 - 20 parts of organosilicon - modified ammonium polyphosphate, 8 - 10 parts of dipentaerythritol, 6 - 8 parts of melamine, 3 - 5 parts of graphene oxide - polyacrylic acid - nano - silica composite, 8 - 12 parts of pigment extender, 4 - 6 parts of zinc phosphate, 4 - 6 parts of additives and 8 - 10 parts of water; The graphene oxide - polyacrylic acid - nano - silica composite is prepared by the following method: S1. Disperse graphene oxide in deionized water, and perform ultrasonic dispersion to obtain a graphene oxide dispersion liquid; add a silane coupling agent thereto, and stir and react at 60 - 70 °C for 4 - 6 h to obtain silane coupling agent - treated graphene oxide; S2. Disperse the silane coupling agent - treated graphene oxide in deionized water, add a polyacrylic acid solution with a mass concentration of 5 - 7%, and stir and react at 60 - 70 °C for 6 - 8 h to obtain a graphene oxide - polyacrylic acid composite; S3. Disperse nano - silica in deionized water, and perform ultrasonic dispersion to obtain a nano - silica dispersion liquid; disperse the graphene oxide - polyacrylic acid composite in deionized water, and perform ultrasonic dispersion to obtain a graphene oxide - polyacrylic acid composite dispersion liquid, mix it with the nano - silica dispersion liquid, stir and react at 60 - 70 °C for 4 - 6 h, perform centrifugal separation, wash with deionized water, and dry to obtain the graphene oxide - polyacrylic acid - nano - silica composite; Among them, the time of ultrasonic dispersion is 1 - 2 h, and the dosage of the silane coupling agent is 1 - 2% of the mass of graphene oxide.

2. A high waterproof and corrosion-resistant fireproof coating according to claim 1, characterized in that, The pigment extender is selected from one or more of silicate, aluminum hydroxide, magnesium hydroxide, aluminum oxide, zinc borate, expanded graphite, nano - clay.

3. A fireproof coating with high waterproof and corrosion resistance according to claim 1, characterized in that, The additives include one or more of a thickener, a leveling agent, a dispersant, and a toughening agent.

4. The preparation method of a highly waterproof and corrosion-resistant fireproof coating according to claim 1, characterized in that, It includes the following steps: A. Premixing: Add waterborne epoxy resin, pure acrylic emulsion, polyurethane emulsion and water into a reaction kettle, and stir evenly; B. Filler dispersion: Add organosilicon - modified ammonium polyphosphate, dipentaerythritol, and melamine into the premixed liquid, and stir at high speed; then add the graphene oxide - polyacrylic acid - nano - silica composite, zinc phosphate, pigment extender, and additives into the premixed liquid, and stir at high speed to obtain a coating; C. Filtration and packaging: Filter the prepared coating to remove impurities, and package and store.

5. The preparation method of a highly waterproof and corrosion-resistant fireproof coating according to claim 4, characterized in that, The stirring rate of high - speed stirring is 800 - 2000 r / min, and the stirring time is 1 - 3 h.

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