Flexible high-solid-content solvent-free epoxy intumescent fireproof coating and preparation method thereof

Abstract

The invention discloses a flexible high-solid-content solvent-free epoxy intumescent fire retardant coating and a preparation method thereof, and relates to the technical field of solvent-free epoxy steel structure fire retardant coatings, the flexible high-solid-content solvent-free epoxy intumescent fire retardant coating is prepared from 15-35 parts of epoxy resin, 2-4 parts of an epoxy diluent, 5-8 parts of toughening resin, 0.2-0.3 part of a dispersing agent, 5-11 parts of reinforcing filler titanium dioxide, 1-3 parts of a curing agent, 1-3 parts of a curing agent and 1-3 parts of a curing agent. The coating is prepared from the following components in parts by weight: 40-55 parts of a flame retardant, 0.50-4 parts of a flatting agent, 1-5 parts of fumed silica, 0.20-1 part of a defoaming agent, 10-18 parts of an alicyclic amine curing agent, 1-1.5 parts of a curing accelerator and 1-5 parts of a plasticizer.

Description

Technical Field

[0001] The present invention relates to the technical field of solvent-free epoxy steel structure fireproof coatings, and particularly relates to a flexible high-solid solvent-free epoxy intumescent fireproof coating and a preparation method thereof. Background Art

[0002] Steel structures have characteristics such as high strength and good toughness, so they are widely used in building structures such as high-speed railway stations, heavy workshops, and airports. Steel structures themselves are not flammable, but they have poor fire resistance. When a bare steel structure catches fire, the temperature quickly rises to the critical temperature, causing its load-bearing capacity to rapidly decline, resulting in the collapse of the building and safety accidents.

[0003] The typical characteristic of solvent-free intumescent epoxy fireproof coatings compared to other types of fireproof coatings is their excellent comprehensive performance. They can not only provide good fire protection, but also have very excellent mechanical strength and anti-corrosion effects. Therefore, they are widely used in various harsh environments, especially for fire protection of offshore steel structures. Solvent-free intumescent epoxy fireproof coatings are mainly applied to industrial steel structures that need to protect against hydrocarbon fires. Because of their high cost, their application in building steel structures is relatively less, and currently they are mainly applied to some steel structures of super-high-standard commercial buildings.

[0004] Solvent-free epoxy intumescent fireproof coatings do not contain solvents, have no impact on construction workers during use; there is no danger of fire and explosion; they do not increase the emissions of VOCs in the atmosphere, especially when repairing buildings in use, they can avoid causing serious impacts on the surrounding environment.

[0005] Chinese Patent CN116694191A discloses a solvent-free epoxy heavy anti-corrosion coating for marine engineering and a preparation method thereof. The A component of the coating is composed of epoxy resin E44, 2602 resin, epoxy active solvent, cenospheres, wet-ground mica flakes, graphite flakes, cast stone powder, titanium dioxide, talc powder, fumed silica, and additives, etc., and can be manufactured at room temperature. The B component is a Mannich addition polyamine curing agent. The product has the characteristics of high performance, economy, environmental friendliness, energy saving, and easy construction. A variety of green and low-carbon technologies are used in the manufacturing process to reduce pollution, save resources, reduce costs, and improve social and economic benefits. The coating has strong adhesion to steel and concrete, a dense structure, resistance to freeze-thaw, resistance to alternating dry-wet, hot-cold, and good impact and abrasion resistance. However, considering that the comparative patent is also a solvent-free epoxy-related patent, and also takes solvent-free and environmental protection as the core points, but the comparative patent uses a Mannich addition polyamine curing agent, and the preparation process of its curing agent is cumbersome and difficult, while the present application uses a toughening resin to improve toughness and increase strength, and the effect is better.

[0006] Chinese patent CN113444425B discloses a water-based epoxy fire retardant coating and its preparation method and application. The water-based epoxy fire retardant coating is composed of component A and component B, wherein component A includes water-based epoxy emulsion, vinyl-epoxy emulsion, carbon-forming catalyst, carbon-forming agent, foaming agent and flame retardant, and component B includes curing agent and refractory fiber. The water-based epoxy fire retardant coating involved in the prior art takes into account the excellent sealing properties of solvent-free epoxy fire retardant coating and high-solid epoxy fire retardant coating, brings excellent corrosion resistance, UV radiation resistance, water resistance, organic solvent resistance, and can be used in harsh outdoor environments. The fire retardant coating of the prior art preferably uses a homemade emulsion, optimizes and adjusts the structure of the film-forming material, and has high fire prevention efficiency. The existing patent is also a patent related to epoxy fire retardant coatings, and also takes flame retardancy and environmental protection as core points. However, considering that the comparative patent uses modified epoxy emulsion, the fire retardant coating it produces has shortcomings such as insufficient toughness and insufficient foaming multiple. The present application uses toughening resin to toughen epoxy resin and cooperates with alicyclic amine curing agent to improve toughness and increase strength, which has better effects. Summary of the invention

[0007] Technical problem to be solved: The purpose of the present invention is to overcome the technical problems existing in the existing solvent-free epoxy intumescent fire-retardant coating technology, such as brittle paint film, high viscosity, poor weather resistance, and the use of Mannich addition polyamine curing agent, the preparation process of which is cumbersome and difficult, and the resulting fire-retardant coating has insufficient toughness and insufficient foaming multiple. The present application provides a flexible high-solid solvent-free epoxy intumescent fire-retardant coating and a preparation method thereof. After a fire occurs, the coating has a high expansion characteristic after combustion, and the thickness of the carbon layer reaches several times or even dozens of times the original thickness, which increases the heat conduction distance and reduces the thermal conductivity, so as to enhance the stability of the later expanded carbon layer in the flame and improve the fire resistance limit of the coating.

[0008] To achieve the above objectives, this application is implemented through the following technical solutions: A flexible high-solid solvent-free epoxy intumescent fire retardant coating. The raw materials are mixed by weight: 15-35 parts of epoxy resin, 2-4 parts of epoxy diluent, 5-8 parts of toughening resin, 0.2-0.3 parts of dispersant, 5-11 parts of reinforcing filler titanium dioxide, 40-55 parts of flame retardant, 0.50-4 parts of leveling agent, 1-5 parts of fumed silica, 0.20-1 parts of defoamer, 10-18 parts of alicyclic amine curing agent, 1-1.5 parts of curing accelerator and 1-5 parts of plasticizer.

[0009] Preferably, the epoxy resin is epoxy resin E-51.

[0010] Preferably, the epoxy diluent is dodecyl glycidyl ether.

[0011] Preferably, the flame retardant is an ammonium polyphosphate-pentaerythritol-melamine system.

[0012] Preferably, the dispersant is talcum powder.

[0013] A preparation method of a flexible high-solid-content solvent-free epoxy intumescent fireproof coating comprises the following steps: Step 1: Add epoxy resin and epoxy diluent into a dispersion tank and stir; Step 2: Add a toughening resin into the dispersion tank and continue stirring; Step 3: Add reinforcing filler titanium dioxide, flame retardant, and fumed silica into the dispersion tank and continue stirring; Step 4: Add an antifoaming agent, a leveling agent, and a plasticizer into the dispersion tank and continue stirring. After stirring evenly, filter and package through a 400-mesh filter screen to obtain Component A; Step 5: Take an alicyclic amine curing agent and a curing accelerator, add them into a disperser, disperse at a speed of 1500 r / min for 5 min, add a dispersant, continue dispersing for 30 min, carry out vacuum defoaming for 0.5 h, and then discharge under normal pressure to obtain Component B; Step 6: Mix Component A and Component B to obtain a flexible high-solid-content solvent-free epoxy intumescent fireproof coating.

[0014] Preferably, in Step 1, the stirring is carried out at a speed of 600 r / min for 5 minutes.

[0015] Preferably, in Step 2, the stirring is carried out at a speed of 800 r / min for 10 minutes.

[0016] Preferably, in Step 3, the stirring is carried out at a speed of 2000 r / min for 40 - 45 minutes.

[0017] Preferably, in Step 4, the stirring is carried out at a speed of 1500 r / min for 20 minutes.

[0018] The technical principle of the present invention is as follows: This patent uses an alicyclic amine curing agent. By introducing flexible components, the flexibility of the coating is significantly improved, making it not easily cracked when subjected to external forces or temperature changes, and extending the service life of the coating. In terms of adaptability, the flexible design enables the coating to better adapt to the deformation of the substrate. Especially on steel structures, it can effectively cope with the stress caused by thermal expansion and contraction or mechanical vibration.

[0019] This application provides a flexible high-solid-content solvent-free epoxy intumescent fireproof coating and its preparation method, having the following beneficial effects: 1. This high-solid-content solvent-free epoxy fireproof coating of the present invention is very friendly to the environment, with extremely low VOC emissions and good flexibility; 2. It has better adhesion, and the paint film will not easily fall off, obtaining a better paint film appearance; 3. The epoxy fireproof coating is an exothermic reaction, and the drying speed of the paint film is fast. 4. Under the requirement of high film thickness of the fireproof coating, the accumulated heat is faster than that of ordinary coatings. Therefore, compared with ordinary solvent-free epoxy coatings, the drying speed is also significantly accelerated, saving costs. 5. The prepared solvent-free epoxy fireproof coating with high solid content has excellent performance. The addition of a flexible curing agent can greatly improve its toughness. The coating formed by the prepared solvent-free epoxy steel structure intumescent fireproof coating has good comprehensive performance. After combustion, the fireproof coating has a large expansion multiple, and the expanded carbon layer is uniform, dense and has high strength. Specific Embodiments

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] In the embodiments of the present application, the toughening resin is purchased from Sami Group; the model is pl-1000s; The dispersant is talc powder, purchased from Degussa; the model is Tego Talc AT 2; The titanium dioxide is purchased from Nanjing Titanium White Chemical Industry; the model is NR950; The flame retardant is an ammonium polyphosphate-pentaerythritol-melamine system, purchased from Sichuan Zhuo'an; The leveling agent is purchased from Degussa; the model is TEGO Glide 432; The fumed silica is purchased from Evonik Shanghai; the model is A200; The defoamer is purchased from Degussa; the model is TEGO Foamex 7447; The alicyclic amine curing agent is purchased from Rich; the model is R-2030; The curing accelerator is purchased from Rich; the model is R-2019K; The plasticizer is purchased from Kingfa Science & Technology, and the model is JFR-ESO-500.

[0022] Example 1: A preparation method of a flexible solvent-free epoxy intumescent fireproof coating with high solid content, comprising the following steps: Step 1: Add 25 g of epoxy resin E-51 and 3 g of epoxy diluent into a dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 50 g of flame retardant and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter through a 400-mesh sieve after stirring evenly, and package to obtain Component A; Step 5: Take 12 g of alicyclic amine curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.2 g of dispersant, continue to disperse for 30 min, carry out vacuum degassing for 0.5 h, and then discharge under normal pressure to obtain Component B; Step 6: Mix Component A and Component B to obtain a flexible high-solid solvent-free epoxy intumescent fireproof coating.

[0023] Example 2: A preparation method of a flexible high-solid solvent-free epoxy intumescent fireproof coating, comprising the following steps: Step 1: Add 30 g of epoxy resin E-51 and 3 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 45 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter through a 400-mesh sieve after stirring evenly, and package to obtain Component A; Step 5: Take 15 g of alicyclic amine curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.3 g of dispersant, continue to disperse for 30 min, carry out vacuum degassing for 0.5 h, and then discharge under normal pressure to obtain Component B; Step 6: Mix Component A and Component B to obtain a flexible high-solid solvent-free epoxy intumescent fireproof coating.

[0024] Example 3: A preparation method of a flexible high-solid solvent-free epoxy intumescent fireproof coating, comprising the following steps: Step 1: Add 35 g of epoxy resin E-51 and 4 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 40 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter through a 400-mesh filter after stirring evenly, and package to obtain Component A; Step 5: Take 10 g of alicyclic amine curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.2 g of dispersant, continue to disperse for 30 min, discharge under normal pressure after vacuum degassing for 0.5 h to obtain Component B; Step 6: Mix Component A and Component B to obtain a flexible high-solid solvent-free epoxy intumescent fireproof coating.

[0025] Example 4: A preparation method of a flexible high-solid solvent-free epoxy intumescent fireproof coating, comprising the following steps: Step 1: Add 20 g of epoxy resin E-51 and 2 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 55 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter through a 400-mesh filter after stirring evenly, and package to obtain Component A; Step 5: Take 10 g of alicyclic amine curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.3 g of dispersant, continue to disperse for 30 min, discharge under normal pressure after vacuum degassing for 0.5 h to obtain Component B; Step 6: Mix Component A and Component B to obtain a flexible high-solid solvent-free epoxy intumescent fireproof coating.

[0026] Example 5: A preparation method of a flexible high-solid solvent-free epoxy intumescent fireproof coating, comprising the following steps: Step 1: Add 30 g of epoxy resin E-51 and 3 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 8 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 50 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter through a 400-mesh sieve after stirring evenly, and package to obtain Component A; Step 5: Take 10 g of alicyclic amine curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.2 g of dispersant, continue to disperse for 30 min, carry out vacuum degassing for 0.5 h, and then discharge under normal pressure to obtain Component B; Step 6: Mix Component A and Component B to obtain a flexible high-solid solvent-free epoxy intumescent fireproof coating.

[0027] Example 6: A preparation method of a flexible high-solid solvent-free epoxy intumescent fireproof coating, comprising the following steps: Step 1: Add 25 g of epoxy resin E-51 and 3 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 8 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 50 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter through a 400-mesh sieve after stirring evenly, and package to obtain Component A; Step 5: Take 12 g of alicyclic amine curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.3 g of dispersant, continue to disperse for 30 min, carry out vacuum degassing for 0.5 h, and then discharge under normal pressure to obtain Component B; Step 6: Mix Component A and Component B to obtain a flexible high-solid solvent-free epoxy intumescent fireproof coating.

[0028] Comparative Example 1: A preparation method of a fireproof coating, the steps are as follows, Step 1: Add 25 g of epoxy resin E-51 and 3 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 50 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter and package through a 400-mesh filter screen after stirring evenly to obtain Component A; Step 5: Take 12 g of polyamide curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.2 g of dispersant, continue to disperse for 30 min, discharge under normal pressure after vacuum defoaming for 0.5 h to obtain Component B; Step 6: Mix Component A and Component B to obtain the fireproof coating.

[0029] Comparative Example 2: A preparation method of a fireproof coating, the steps are as follows: Step 1: Add 25 g of epoxy resin E-51 and 3 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 50 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter and package through a 400-mesh filter screen after stirring evenly to obtain Component A; Step 5: Take 12 g of aliphatic amine curing agent and 1 g of curing accelerator, add them into the disperser, disperse at a speed of 1500 r / min for 5 min, add 0.2 g of dispersant, continue to disperse for 30 min, discharge under normal pressure after vacuum defoaming for 0.5 h to obtain Component B; Step 6: Mix Component A and Component B to obtain the fireproof coating.

[0030] Comparative Example 3: A preparation method of a fireproof coating, the steps are as follows: Step 1: Add 25 g of epoxy resin E-51 and 3 g of epoxy diluent into the dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin into the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 50 g of flame retardant, and 1 g of fumed silica into the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer into the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, filter and package through a 400-mesh filter screen after stirring evenly to obtain Component A; Step 5: Take 12 g of aromatic amine curing agent and 1 g of curing accelerator, add them to a disperser, disperse at a speed of 1500 r / min for 5 min, add 0.2 g of dispersant, continue to disperse for 30 min, carry out vacuum degassing for 0.5 h, and then discharge under normal pressure to obtain Component B; Step 6: Mix Component A and Component B to obtain the fireproof coating.

[0031] Comparative Example 4: A preparation method of a fireproof coating, the steps are as follows: Step 1: Add 25 g of epoxy resin E-51 and 3 g of epoxy diluent to a dispersion tank and disperse at a speed of 600 r / min for 5 minutes; Step 2: Add 5 g of toughening resin to the dispersion tank and disperse at a speed of 800 r / min for 10 minutes; Step 3: Add 10 g of reinforcing filler titanium dioxide, 50 g of flame retardant, and 1 g of fumed silica to the dispersion tank and disperse at a speed of 2000 r / min for 45 minutes; Step 4: Add 0.5 g of defoamer, 0.5 g of leveling agent, and 1 g of plasticizer to the dispersion tank, disperse at a speed of 1500 r / min for 20 minutes, stir well, filter through a 400-mesh filter screen and package to obtain Component A; Step 5: Take 12 g of anhydride curing agent and 1 g of curing accelerator, add them to a disperser, disperse at a speed of 1500 r / min for 5 min, add 0.2 g of dispersant, continue to disperse for 30 min, carry out vacuum degassing for 0.5 h, and then discharge under normal pressure to obtain Component B; Step 6: Mix Component A and Component B to obtain the fireproof coating.

[0032] Performance test: Determine the fire resistance limit, foaming multiple, bonding strength, water resistance, resistance to neutral salt spray, and resistance to temperature change cycling performance of the waterborne intumescent steel structure fireproof coatings in Examples 1-6 and Comparative Examples 1-4.

[0033] The fire resistance limit of the solvent-free epoxy fireproof coating is determined by the following method: After the prepared sample plate is cured for 7 days, fix it on an iron stand with the side coated with the fireproof coating facing down, use a spray gun to burn it, and use an infrared thermometer to check the temperature on the back of the steel plate. The time used when the temperature reaches 580 °C is the fire resistance limit of the coating.

[0034] The foaming multiple of the solvent-free epoxy fireproof coating is determined by the following method: The ratio of the height after expansion of the fireproof coating after combustion to the thickness before combustion.

[0035] The bond strength of the solvent-free epoxy fireproof coating is determined by the following method: Apply the binder evenly within an area of 40 mm x 40 mm at the center of the sample plate, then stick the steel connector and press a 1 kg weight on it. Carefully remove the binder around the connection. After placing it for 3 days, apply a tensile force in the vertical direction of the specimen bottom plate and apply the load at a speed of 1500 N / min to 2000 N / min. Measure the maximum tensile load. The bond strength of each specimen is calculated according to Equation (1).

[0036] f = F / A Equation (1) Where: f—the bond strength, in megapascals (MPa); F—the maximum load, in newtons (N); A—the bond area, in square millimeters (mm 2 ); The test results of various properties of Examples 1-6 and Comparative Examples 1-4 are shown in Table 1 as follows: Table 1 Comparison of test results of various properties of Examples 1-6 and Comparative Examples 1-4: .

[0037] As can be seen from Table 1, the solvent-free epoxy intumescent fireproof coatings prepared in Examples 1-6 of the present invention. Among them, in Example 2, its fire resistance limit is 87 minutes, the foaming multiple is 10 times, the bond strength is 15.60 MPa, and there are no abnormalities in water resistance, neutral salt spray resistance and temperature change cycle resistance.

[0038] Compared with Examples 1-6, Comparative Example 1 is a conventional formula for preparing solvent-free epoxy intumescent fireproof coatings on the market, and the polyamide curing agent is used. It can be seen that its fire resistance time is only 68 min, it blisters after 480 h of salt spray resistance, and it blisters during 8 cycles of temperature change cycle resistance, and its performance does not meet the standards. From the result data of different epoxy curing agents on solvent-free epoxy intumescent fireproof coatings in Comparative Examples 2-4, it can be seen that the fireproof performance has been improved to varying degrees compared with Comparative Example 1.

[0039] The toughening resin involved in this application is purchased from Miki Group: the model is pl-1000s (HiRENOL PL -1000S), which is an aromatic liquid hydrocarbon resin and a thermoplastic resin. When cracks appear in the epoxy resin matrix, the molecular chains of HiRENOL PL - 1000S resin can span both sides of the crack and connect both sides of the crack like a bridge.Due to its certain flexibility and strength, it can withstand a certain tensile force, thereby preventing cracks from further expanding, enabling the material to consume more energy during the fracture process, and improving toughness. Therefore, the bond strength (pull-out strength) tested in this application ≥ 14.48 MPa (specifically 14.48 - 16.50 MPa). Moreover, when the pl-1000s described in this application is used in combination with an alicyclic amine curing agent and a curing accelerator, the three produce a synergistic effect, which can bring the effect of further increasing the bond strength. For example, when the pl-1000s is used in combination with an alicyclic amine curing agent and a curing accelerator as described in Example 2, the bond strength is 15.60 MPa, while when the pl-1000s is used in combination with an aromatic amine curing agent and a curing accelerator as described in Comparative Example 2, the bond strength is only 13.43 MPa. The principle of the synergistic effect is as follows: The specifically used alicyclic amine curing agent in this application causes the toughened resin to undergo a cross-linking reaction, forming a three-dimensional network structure, thereby improving the bond strength and mechanical properties of the resin. Further explanation of the mechanism is: The alicyclic amine curing agent undergoes a chemical reaction with the active groups in the toughened resin pl-1000s. The epoxy group in epoxy resin E51 undergoes a ring-opening addition reaction with the amino group in the alicyclic amine curing agent, forming a cross-linking network. Through the curing reaction, the resin molecules change from a linear or branched structure to a three-dimensional network structure, and the intermolecular force is enhanced, thereby improving the cohesion and bond strength of the resin. At the same time, the dosage of the alicyclic amine curing agent will affect the rate and degree of the curing reaction, and thus affect the performance of the resin. Therefore, in the claims of this application, 10 - 18 parts of the alicyclic amine curing agent and 5 - 8 parts of the toughened resin are selected, and under the curing conditions, the resin can be fully cured to obtain a good bonding effect; when the alicyclic amine curing agent and the curing accelerator react with pl-1000s together, the reaction between the toughened resin and the curing agent is accelerated, enabling the curing reaction to be completed at a lower temperature or in a shorter time, which is beneficial to improving production efficiency and bond strength. The alicyclic amine curing agent and the curing accelerator can reduce the activation energy of the curing reaction and accelerate the reaction rate between the alicyclic amine curing agent and the active groups in the resin. In the epoxy resin E51 system of this application, the alicyclic amine curing agent and the curing accelerator can form a complex with the epoxy group in epoxy resin E51, increasing the activity of the epoxy group and making it easier to react with the alicyclic amine curing agent. The addition of the alicyclic amine curing agent and the curing accelerator can make the curing reaction more complete, improve the cross-linking density and bond strength of the resin. At the same time, the dosages of the alicyclic amine curing agent and the curing accelerator need to be adjusted according to the specific epoxy resin E51 and alicyclic amine curing agent system to achieve the best effect. The introduction of this distinguishing technical feature has achieved the technical effects of high strength and strong toughness, thereby solving the technical problem of the brittleness of epoxy coatings.

[0040] The present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, various changes and improvements are possible, and all such changes and improvements fall within the scope of the present invention claimed.

Claims

1. A flexible high-solid solvent-free epoxy intumescent fire retardant coating, characterized in that: The raw materials are mixed by mass: 15-35 parts of epoxy resin, 2-4 parts of epoxy diluent, 5-8 parts of toughening resin, 0.2-0.3 parts of dispersant, 5-11 parts of reinforcing filler titanium dioxide, 40-55 parts of flame retardant, 0.50-4 parts of leveling agent, 1-5 parts of fumed silica, 0.20-1 parts of defoaming agent, 10-18 parts of alicyclic amine curing agent, 1-1.5 parts of curing accelerator and 1-5 parts of plasticizer; the toughening resin model is pl-1000s.

2. The flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 1, characterized in that: The epoxy resin is epoxy resin E-51.

3. The flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 1, characterized in that: The epoxy diluent is dodecyl glycidyl ether.

4. The flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 1, characterized in that: The flame retardant is an ammonium polyphosphate-pentaerythritol-melamine system.

5. The flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 1, characterized in that: The dispersant is talc.

6. A method for preparing the flexible high solid solvent-free epoxy intumescent fire retardant coating according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Add epoxy resin and epoxy diluent into the dispersion tank and stir; Step 2: Add toughening resin into the dispersion tank and continue stirring; Step 3: Add reinforcing filler titanium dioxide, flame retardant, and fumed silica into the dispersion tank and continue stirring; Step 4: Add defoamer, leveling agent and plasticizer to the dispersion tank and continue stirring. After stirring evenly, filter and package through a 400-mesh filter to obtain component A; Step 5: Take alicyclic amine curing agent and curing accelerator, add them into a disperser, disperse at 1500r / min for 5 minutes, add dispersant, continue to disperse for 30 minutes, vacuum degas for 0.5 hours, and then discharge at normal pressure to obtain component B; Step 6: Mix component A with component B to obtain a flexible high-solid solvent-free epoxy intumescent fire retardant coating.

7. The method for preparing the flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 6, characterized in that: In step 1, the stirring is carried out at a speed of 600 r / min for 5 minutes.

8. The method for preparing the flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 6, characterized in that: In step 2, the stirring is carried out at a speed of 800 r / min for 10 minutes.

9. The method for preparing the flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 6, characterized in that: In step 3, the stirring is carried out at a speed of 2000 r / min for 40-45 minutes.

10. The method for preparing the flexible high solid solvent-free epoxy intumescent fire retardant coating according to claim 6, characterized in that: In step 4, the stirring is carried out at a speed of 1500 r / min for 20 minutes.