An environment-friendly waterborne intumescent fireproof coating and its preparation method

Abstract

The present invention discloses an environment-friendly waterborne intumescent fireproof coating and a preparation method thereof, relating to the field of fireproof coatings. The coating comprises a film-forming substance, a foaming agent, a dehydrating agent, a synergistic flame retardant, a fiber gel, pigments and fillers, an auxiliary agent and distilled water, and the synergistic flame retardant is Salen-based polyphosphazene composite magnesium-aluminum layered double hydroxide. The present invention realizes the preparation of a composite flame retardant of an organic phosphorus-nitrogen compound and an inorganic double-metal hydroxide. The Salen-based polyphosphazene composite magnesium-aluminum layered double hydroxide is a novel halogen-free flame retardant. When used in combination with the foaming agent and the dehydrating agent, it self-forms a flame retardant synergistic system, which not only reduces the addition amounts of the foaming agent and the dehydrating agent, but also improves the flame retardant and fire resistance performance and storage stability of the waterborne intumescent fireproof coating. When encountering fire, it can expand and foam to form a fluffy, uniform and dense expanded carbon layer, solving the problem of insufficient fire resistance of the waterborne intumescent fireproof coating; it also solves the problem of a large amount of smoke released when traditional organic fireproof coatings are heated.

Description

Technical Field

[0001] The present invention relates to the technical field of fireproof coatings, and specifically to an environment-friendly water-based intumescent fireproof coating and a preparation method thereof. Background Art

[0002] Fireproof coatings are a special functional coating that can effectively prevent or delay the spread of fire. Compared with other fire protection materials, fireproof coatings have the advantages of easy construction, low cost, good heat insulation, etc., and are widely used in many places such as steel structure buildings, cable protection, highway tunnels, and airports. According to different base materials, fireproof coatings can be divided into inorganic fireproof coatings and organic fireproof coatings. Inorganic fireproof coatings contain inorganic heat-resistant flame retardant fillers and mainly rely on the non-combustibility of the material itself for fire protection. They do not expand and foam. Due to their low density and small overall thermal conductivity of the material, they have excellent fire resistance. However, inorganic fireproof coatings usually need to be applied to more than 20 - 30 mm. The coating is rough in appearance due to the inclusion of inorganic mineral materials, has poor decorative properties, and is prone to embrittlement, cracking, and peeling. Conventional organic fireproof coatings include oil-based intumescent fireproof coatings and water-based intumescent fireproof coatings. Organic fireproof coatings can expand and foam to form a heat-insulating fireproof layer, and have the advantages of fine particle size, thin coating, convenient construction, and good decorative properties. Among them, oil-based intumescent fireproof coatings are widely used because of their excellent fire resistance and good physical and chemical properties, and can usually meet the fire resistance limit of less than 2.5 h. However, its diluent is an organic solvent with a high VOC content, and there are significant problems of environmental pollution and harm to human health during production and construction. Therefore, with the increasingly strict environmental protection regulations, it will also be replaced by water-based products in the future. Although there are already water-based intumescent fireproof coatings in the market, there are still many problems such as insufficient fire resistance, large smoke generation of the coating, poor weather resistance, and poor storage stability. Summary of the Invention

[0003] The purpose of the present invention is to provide an environment-friendly water-based intumescent fireproof coating containing a high-efficiency smoke suppressant and flame retardant and a preparation method thereof, aiming at the deficiencies of existing water-based intumescent fireproof coatings, such as insufficient fire resistance, large smoke generation, and unstable storage.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] An environment-friendly water-based intumescent fireproof coating, comprising the following raw materials in weight percentages: 20% - 30% film-forming substance, 2% - 5% foaming agent, 5% - 7% dehydrating agent, 10% - 15% synergistic flame retardant, 2% - 5% fiber gel, 16% - 20% pigment and filler, 3.5% - 5.0% auxiliary agent, and the balance being distilled water.

[0006] In some preferred embodiments of the present invention, the film-forming substance is one or more of vinyl acetate emulsion, pure acrylic emulsion, vinyl acetate-acrylic emulsion, water-soluble phenolic resin, styrene-acrylic emulsion, and silicone-acrylic emulsion, and the glass transition temperature of the film-forming substance is 35°C < Tg < 45°C.

[0007] In some preferred embodiments of the present invention, the dehydrating agent is ammonium polyphosphate and / or melamine phosphate, wherein the degree of polymerization of ammonium polyphosphate is > 1000.

[0008] In some preferred embodiments of the present invention, the foaming agent is one or more of melamine, dicyandiamide, and chlorinated paraffin.

[0009] In some preferred embodiments of the present invention, the pigment and filler include one or more of titanium dioxide, kaolin, aluminum hydroxide, magnesium hydroxide, and talc powder.

[0010] In some preferred embodiments of the present invention, the auxiliaries include one or more of wetting and dispersing agents, preservatives, defoaming agents, pH regulators, leveling agents, viscosity reducers, antifreeze agents, and film-forming aids.

[0011] In some preferred embodiments of the present invention, the fiber gel is prepared from one or more of glass fiber, carbon fiber, aluminum silicate fiber, sepiolite fiber, alumina fiber, basalt fiber, and high silica fiber, and the fiber diameter used is 5 - 8 μm, and the aspect ratio is 20:1 - 25:1.

[0012] Preferably, the fiber gel is prepared by the following method: Divide distilled water into two parts, distilled water a and distilled water b, in a ratio of 4:1. Preheat distilled water a to 60 - 65°C, adjust the stirring speed to 500 - 800 rad / min, add 3 wt% of silane-modified hydroxypropyl methyl cellulose based on the total amount of distilled water, then add 1 wt% of Camine 328 auxiliary based on the total amount of distilled water, keep stirring for 30 min. After the system shows a gel state, add distilled water b, slowly add 28 - 36 wt% of fiber, adjust the stirring speed to 800 - 1000 rad / min, and stir until the fiber is uniformly dispersed in the gel to obtain the fiber gel.

[0013] In some preferred embodiments of the present invention, the synergistic flame retardant is Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide (Sa len-PZN@MgAl-LDH).

[0014] As a further improvement of the present invention, the Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide is prepared by the following method:

[0015] (1) React 2,4-dihydroxybenzaldehyde, o-phenylenediamine, hexachlorocyclotriphosphazene and triethylamine to obtain Salen-based polyphosphazene (Salen-PZN), ultrasonically disperse it in distilled water to obtain a Salen-PZN suspension for standby;

[0016] (2) Dissolve magnesium salt and aluminum salt in distilled water and then add them to the Salen-PZN suspension, and adjust the pH to 8-12 to obtain a suspension;

[0017] (3) Put the suspension into a hydrothermal reaction kettle, heat it up to 80-180 °C for reaction, after the reaction is completed, centrifuge at a speed of 8000-12000 r / min, freeze-dry for 24-48 h, and grind to obtain Salen-based polyphosphazene composite magnesium-aluminum layered double hydroxide.

[0018] Preferably, in step (1), the preparation method of the Salen-PZN is as follows:

[0019] A. Dissolve 2,4-dihydroxybenzaldehyde in organic solvent a to obtain solution a;

[0020] B. Dissolve o-phenylenediamine in organic solvent a, and then slowly drop it into solution a to obtain solution b;

[0021] C. React solution b at 10-40 °C for 8-24 h, filter, wash, and vacuum dry to obtain Salen-H6;

[0022] D. Disperse Salen-H6 in organic solvent b to obtain solution c;

[0023] E. Ultrasonically disperse hexachlorocyclotriphosphazene in organic solvent b, and then slowly drop it into solution c to obtain a mixture of Salen-H6 and hexachlorocyclotriphosphazene;

[0024] F. Add triethylamine to the mixture, heat it up to 20-60 °C for reaction for 4-12 h, after the reaction stops, filter, wash, and vacuum dry to obtain Salen-PZN.

[0025] More preferably, in steps A and B, the molar ratio of 2,4-dihydroxybenzaldehyde to o-phenylenediamine is (2.0-4.0):1.

[0026] More preferably, in steps A and B, the organic solvent a is one of methanol, ethanol, pentaerythritol, dichloromethane, and chloroform.

[0027] More preferably, in steps C-F, the molar ratio of Salen-H6 to hexachlorocyclotriphosphazene and triethylamine is (3-6):1:(8-10).

[0028] More preferably, in step C, the temperature of vacuum drying is 40-80 °C, and the time is 12-24 h.

[0029] More preferably, in steps D and E, the organic solvent b is one of methanol, ethanol, acetonitrile, tetrahydrofuran, and acetone.

[0030] More preferably, in step F, the temperature of vacuum drying is 60-100 °C, and the time is 12-24 h.

[0031] Preferably, in step (1), the power of ultrasonic dispersion is 100-300 W, and the time is 5-10 min.

[0032] Preferably, in step (2), the mass ratio of Sa len-PZN to magnesium salt and aluminum salt is 1:(10-15):(5-8).

[0033] Preferably, in step (2), Mg 2+ in the magnesium salt and Al 3+ in the aluminum salt has a molar ratio of (1-4):1.

[0034] The present invention also provides a preparation method of the above-mentioned environment-friendly water-based intumescent fireproof coating, including the following steps:

[0035] S1. Add part of distilled water into a clean container, start stirring and keep it at 300-500 rad / min. Add a wetting and dispersing agent, a pH regulator, and part of an antifoaming agent in sequence. After adding, adjust the stirring speed to 1500-1800 rad / min, and continue stirring for 15-20 min;

[0036] S2. Under the stirring state, continue to add a dehydrating agent, a foaming agent, and pigments and fillers into the container in sequence. Then add part of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2000-2500 rad / min, and continue stirring for 45-60 min;

[0037] S3. Under the stirring state, continue to add a synergistic flame retardant and a viscosity reducer into the container in sequence. Then add part of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2500-2800 rad / min, and continue stirring for 10-15 min;

[0038] S4. Adjust the stirring speed to 800-1000 rad / min, and continue to add a film-forming substance, a preservative, a leveling agent, an antifreeze agent, a film-forming aid, and the remaining part of the antifoaming agent into the container, and stir for 8-15 min;

[0039] S5. Adjust the stirring speed to 500 - 800 rad / min, continue to add fiber gel into the container, and continue stirring for 10 - 15 min after adding is completed to obtain the finished product.

[0040] Compared with the prior art, the present invention adopting the above technical solution has at least the following beneficial effects:

[0041] 1. In the waterborne intumescent fire - retardant coating of the present invention, a Salen - based polyphosphazene composite magnesium - aluminum layered double hydroxide with high phosphorus and nitrogen content is used as a synergistic flame retardant, which is used in combination with a foaming agent and a dehydrating agent. Without adding a char - forming agent, it self - forms a flame - retardant synergistic system, not only reducing the addition amounts of the foaming agent and the dehydrating agent, but also improving the flame - retardant and fire - resistant properties of the waterborne intumescent fire - retardant coating. When encountering fire, it expands and foams to form a fluffy, uniform and dense expanded carbon layer, and the fire - resistant time can reach 120 min, significantly improving the fire - prevention performance, solving the problem of insufficient fire - resistance of the waterborne intumescent fire - retardant coating, and also providing room for increasing the dosage of pigments and fillers in the system, further reducing the production cost of the coating.

[0042] 2. The present invention combines organophosphazene derivatives with inorganic magnesium - aluminum double hydroxides to realize the preparation of a composite flame retardant of an organic phosphorus - nitrogen - based compound and an inorganic double - metal hydroxide. The prepared Salen - based polyphosphazene composite magnesium - aluminum layered double hydroxide is a novel halogen - free flame retardant with a large surface area and a layered structure, and has high compatibility with polymers. When applied to fire - retardant coatings, it carbonizes into a carbon - rich skeleton at high temperature, and this skeleton structure has the advantages of chemical inertness, non - toxicity and good stability, thus making the product have excellent durability, weather resistance and chemical resistance, solving the problems of poor fire - resistance and weather resistance of the waterborne intumescent fire - retardant coating; and the high char residue can replace the char - forming agent, avoiding the problem of easy migration and precipitation of conventional char - forming agents (such as pentaerythritol), and significantly reducing the release amount of toxic flue gas generated when the coating is heated, solving the problem of large flue gas release amount of traditional organic fire - retardant coatings when heated.

[0043] 3. The present invention prepares refractory fibers into a gel state, which not only ensures the reinforcement and fire - resistance of the refractory fibers, but also prevents the fibers from being sheared and damaged. At the same time, in the form of a gel, it provides sediment - proof and water - retention properties for the system. At a high pigment volume concentration, the product has good storage stability, water resistance and freeze - thaw resistance. The product can be stored at room temperature for 12 months without stratification or precipitation, and the coating has good adhesion, and there are no cracks or peeling phenomena after thorough drying. Description of the Drawings

[0044] Figure 1 is the synthesis route diagram of Salen - PZN@MgAl - LDH in Examples 1 - 3 of the present invention;

[0045] Figure 2 is the infrared spectrogram in Test Example 1 of the present invention;

[0046] Figure 3 It is the SEM image in Test Example 1 of the present invention;

[0047] Figure 4 It is the thermogravimetric image in Test Example 1 of the present invention;

[0048] Figure 5 It is the XRD test image in Test Example 1 of the present invention; Detailed implementation manners

[0049] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] Preparation of Salen-PZN@MgAl-LDH in Example 1

[0051] Please refer to the attached Figure 1 As shown, the synthesis route shown in Figure 1 is adopted in this embodiment to prepare Salen-PZN@MgAl-LDH.

[0052] Ⅰ. Preparation of Salen-based polyphosphazene (Salen-PZN)

[0053] A. Dissolve 5.00 g of 2,4-dihydroxybenzaldehyde in 150 mL of absolute ethanol. The solution is brownish-red. Place it on a magnetic stirrer at 20 °C and perform magnetic stirring at 500 rpm to obtain solution a;

[0054] B. Ultrasonically dissolve 1.78 g of o-phenylenediamine in 40 mL of absolute ethanol with a power of 200 W for 5 min, and then slowly add it dropwise to solution a to obtain solution b;

[0055] C. Continuously stir solution b magnetically for 12 h. After the reaction is completed, a yellow solution is obtained. Filter the product by suction to obtain a yellow solid powder. Wash the powder three times with ethanol and then dry it in vacuum at 65 °C for 24 h to obtain Salen-H6;

[0056] D. Disperse 4.0 g of Salen-H6 in 100 mL of acetonitrile and stir magnetically to obtain solution c;

[0057] E. Ultrasonically disperse 1.0 g of hexachlorocyclotriphosphazene in 50 mL of acetonitrile with an ultrasonic power of 200 W for 5 min;

[0058] F. Heat the solution c in an oil bath to 40 °C, add 20 mL of triethylamine to it, and slowly dropwise add a suspension of hexachlorocyclotriphosphazene over a period of 20 min. The solution changes from yellow to brownish-red and then back to yellow. Continue magnetic stirring for 6 h. After the reaction is complete, filter, wash, and dry in vacuo at 70 °C for 24 h to obtain Sa len-PZN.

[0059] Ⅱ. Preparation of Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide (Sa len-PZN@MgAl-LDH)

[0060] (1). Take 0.80 g of Sa len-PZN, ultrasonically disperse it in 35 mL of distilled water at a power of 200 W for 10 min to obtain a Sa len-PZN dispersion for standby.

[0061] (2). Dissolve 15.25 g of magnesium salt and 7.44 g of aluminum salt in the Sa len-PZN dispersion, and adjust the pH of the mixture to 10.0 using NaOH solution to obtain a suspension.

[0062] (3). Place the suspension in a hydrothermal reaction kettle, heat it to 120 °C and react for 20 h. After the reaction is complete, centrifuge at 8000 r / min, freeze-dry for 24 h, and grind to obtain Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide.

[0063] Example 2 Preparation of Sa len-PZN@MgAl-LDH

[0064] Please refer to the appendix Figure 1 as shown. This example uses the synthetic route Figure 1 shown to prepare Sa len-PZN@MgAl-LDH.

[0065] Ⅰ. Preparation of Sa len-based polyphosphazene (Sa len-PZN)

[0066] A. Dissolve 10.00 g of 2,4-dihydroxybenzaldehyde in 150 mL of absolute ethanol. The solution is brownish-red. Place it on a magnetic stirrer at 20 °C and perform magnetic stirring at 500 rpm to obtain solution a.

[0067] B. Ultrasonically dissolve 3.56 g of o-phenylenediamine in 50 mL of absolute ethanol at a power of 200 W for 5 min, and then slowly dropwise add it to solution a to obtain solution b.

[0068] C. Continuously perform magnetic stirring on solution b for 12 h. After the reaction is complete, a yellow solution is obtained. Filter the product to obtain a yellow solid powder. Wash the powder three times with ethanol and then dry it in vacuo at 65 °C for 24 h to obtain Sa len-H6.

[0069] D. Disperse 4.25 g of Sa len-H6 in 100 mL of acetonitrile and stir magnetically to obtain solution c;

[0070] E. Ultrasonically disperse 1.0 g of hexachlorocyclotriphosphazene in 50 mL of acetonitrile with an ultrasonic power of 200 W for 5 min;

[0071] F. Heat solution c to 40 °C in an oil bath, add 35 mL of triethylamine to it, and slowly dropwise add the suspension of hexachlorocyclotriphosphazene over 20 min. The solution changes from yellow to brownish red and then to yellow. Continue magnetic stirring for 6 h. After the reaction is completed, filter, wash, and dry in vacuo at 70 °C for 24 h to obtain Sa len-PZN.

[0072] II. Preparation of Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide (Sa len-PZN@MgAl-LDH)

[0073] (1) Take 1.0 g of Sa len-PZN and ultrasonically disperse it in 40 mL of distilled water with an ultrasonic power of 200 W for 10 min to obtain a Sa len-PZN dispersion for standby;

[0074] (2) Dissolve 10 g of magnesium salt and 4.88 g of aluminum salt in the Sa len-PZN dispersion, and adjust the pH of the mixture to about 10.0 with NaOH solution to obtain a suspension;

[0075] (3) Place the suspension in a hydrothermal reaction kettle, heat it to 120 °C and react for 20 h. After the reaction is completed, centrifuge at 8000 r / min, freeze-dry for 24 h, and grind to obtain Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide.

[0076] Example 3 Preparation of Sa len-PZN@MgAl-LDH

[0077] Please refer to the appendix Figure 1 as shown. In this example, the synthesis route shown Figure 1 is used to prepare Sa len-PZN@MgAl-LDH.

[0078] I. Preparation of Sa len-based polyphosphazene (Sa len-PZN)

[0079] A. Dissolve 4.40 g of 2,4-dihydroxybenzaldehyde in 100 mL of absolute ethanol. The solution is brownish red. Place it on a magnetic stirrer at 20 °C and stir magnetically at 500 rpm to obtain solution a;

[0080] B. Ultrasonically dissolve 1.57 g of o-phenylenediamine in 40 mL of absolute ethanol at a power of 200 W for 5 min, and then slowly add it dropwise to solution a to obtain solution b;

[0081] C. Continuously stir solution b magnetically for 12 h. After the reaction is completed, a yellow solution is obtained. After filtering the product, a yellow solid powder is obtained. The powder is washed three times with ethanol and then vacuum dried at 65 °C for 24 h to obtain Sa len-H6;

[0082] D. Disperse 2.0 g of Sa len-H6 in 100 mL of acetonitrile and stir magnetically to obtain solution c;

[0083] E. Ultrasonically disperse 0.5 g of hexachlorocyclotriphosphazene in 40 mL of acetonitrile at an ultrasonic power of 200 W for 5 min;

[0084] F. Heat solution c to 40 °C in an oil bath, add 15 mL of triethylamine to it, and slowly dropwise add the suspension of hexachlorocyclotriphosphazene. The dropping time is 20 min, and the solution changes from yellow to brownish red and then to yellow. Continuously stir magnetically for 6 h. After the reaction is completed, filter, wash, and vacuum dry at 70 °C for 24 h to obtain Sa len-PZN.

[0085] II. Preparation of Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide (Sa len-PZN@MgAl-LDH)

[0086] (1) Take 0.80 g of Sa len-PZN and ultrasonically disperse it in 25 mL of distilled water at an ultrasonic power of 200 W for 10 min to obtain a Sa len-PZN dispersion for standby;

[0087] (2) Dissolve 9.61 g of magnesium salt and 4.69 g of aluminum salt in the Sa len-PZN dispersion, and adjust the pH of the mixture to about 10.0 with NaOH solution to obtain a suspension;

[0088] (3) Place the suspension in a hydrothermal reaction kettle, heat it to 120 °C and react for 20 h. After the reaction is completed, centrifuge at a speed of 8000 r / min, freeze dry for 24 h, and grind to obtain the Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide.

[0089] Test Example 1 Performance Test of Sa len-PZN@MgAl-LDH

[0090] (1) Take the Sa len-PZN@MgAl-LDH, Sa len-PZN and MgAl-LDH prepared in Example 1 and put them into an infrared spectrometer. The obtained infrared spectra are as Figure 2 shown.

[0091] It can be seen from Figure 2 that the appearance of new characteristic peaks in the infrared spectrogram indicates the successful synthesis of Sa len-PZN@MgAl-LDH.

[0092] (2) Take the Sa len-PZN@MgAl-LDH, Sa len-PZN and MgAl-LDH prepared in Example 2 and put them into a scanning electron microscope. The obtained SEM image is as Figure 3 shown.

[0093] It can be seen from Figure 3 that the smooth surface of the Sa len-PZN microspheres is obviously wrapped by a lamellar structure.

[0094] (3) Take the Sa len-PZN@MgAl-LDH and Sa len-PZN prepared in Example 3 and put them into a thermogravimetric analyzer. The obtained thermogravimetric diagram is as Figure 4 shown.

[0095] It can be seen from Figure 4 that after MgAl-LDH is successfully coated on the surface of Sa len-PZN, its thermal stability is significantly improved.

[0096] (4) Take the Sa len-PZN@MgAl-LDH and MgAl-LDH prepared in Example 2 and conduct XRD tests. The obtained XRD test diagram is as Figure 5 shown.

[0097] It can be seen from Figure 5 that MgAl-LDH has a high crystallinity and the crystal plane of the synthesized Sa len-PZN@MgAl-LDH does not shift, indicating that MgAl-LDH is only coated on the surface of the Sa len-PZN microspheres.

[0098] Preparation of the fiber gel in Example 4

[0099] Take 50 g of distilled water and divide it into two parts, distilled water a and distilled water b, in a ratio of 4:1. Preheat distilled water a to 60 °C, adjust the stirring speed to 500 rad / min, add 1.5 g of silane-modified hydroxypropyl methylcellulose, and then add 0.5 g of Camine 328 additive. Keep stirring for 30 min. After the system shows a gel state, add distilled water b, slowly add 14 - 18 g of fibers, adjust the stirring speed to 800 - 1200 rad / min, and stir for 30 - 40 min until the fibers are evenly dispersed in the gel, thus obtaining a stably dispersed fiber gel.

[0100] Specifically, the fibers in this embodiment can be selected from one or more of glass fiber, carbon fiber, aluminum silicate fiber, sepiolite fiber, alumina fiber, basalt fiber, and high silica oxygen fiber, and the fiber diameter used is 5 - 8 μm, and the aspect ratio is 20:1 - 25:1.

[0101] Preparation of Environmentally Friendly Waterborne Intumescent Fire Retardant Coating in Example 5

[0102] S1. Add 20 g of distilled water into a clean container, start stirring and keep it at 500 rad / min. Sequentially add 0.3 g of wetting and dispersing agent, 0.2 g of pH regulator, and 0.2 g of defoaming agent. After adding, adjust the stirring speed to 1500 rad / min and continue stirring for 15 min;

[0103] S2. Under the stirring state, sequentially add 5 g of ammonium polyphosphate, 2 g of chlorinated paraffin, 10 g of titanium dioxide, and 10 g of kaolin into the container. Then add 5 g of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2000 rad / min and continue stirring for 45 min;

[0104] S3. Under the stirring state, sequentially add 15 g of synergistic flame retardant and 1.2 g of viscosity reducer into the container. Then add 3.0 g of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2500 rad / min and continue stirring for 10 min;

[0105] S4. Adjust the stirring speed to 800 rad / min, and continue to add 17 g of polyvinyl acetate emulsion, 3 g of vinyl acetate - acrylate emulsion, 0.1 g of preservative, 1.1 g of antifreeze, 1.7 g of film - forming aid, and 0.2 g of defoaming agent into the container, and stir for 8 min;

[0106] S5. Adjust the stirring speed to 500 rad / min, and continue to add 5 g of glass fiber gel into the container. After adding, continue stirring for 15 min to obtain the finished product.

[0107] Preparation of Environmentally Friendly Waterborne Intumescent Fire Retardant Coating in Example 6

[0108] S1. Add 20 g of distilled water into a clean container, start stirring and keep it at 500 rad / min. Sequentially add 0.3 g of wetting and dispersing agent, 0.2 g of pH regulator, and 0.3 g of defoaming agent. After adding, adjust the stirring speed to 1500 rad / min and continue stirring for 15 min;

[0109] S2. While stirring, sequentially add 7 g of ammonium polyphosphate, 5 g of melamine, 16 g of titanium dioxide, and 4 g of aluminum hydroxide into the container in order. Then add 5 g of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2000 rad / min and continue stirring for 45 min;

[0110] S3. While stirring, sequentially add 12 g of synergistic flame retardant and 1.0 g of viscosity reducer into the container in order. Then add 2.0 g of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2500 rad / min and continue stirring for 10 min;

[0111] S4. Adjust the stirring speed to 800 rad / min, and continue to add 17 g of polyvinyl acetate emulsion, 5 g of styrene-acrylic emulsion, 0.1 g of leveling agent, 1.0 g of antifreeze, 2.0 g of film-forming aid, and 0.1 g of defoamer into the container, and stir for 8 min;

[0112] S5. Adjust the stirring speed to 500 rad / min, and continue to add 2 g of aluminosilicate fiber gel into the container. After adding, continue stirring for 10 min to obtain the finished product.

[0113] Preparation of Environmentally Friendly Waterborne Intumescent Fire Retardant Coating in Example 7

[0114] S1. Add 20 g of distilled water into a clean container, start stirring and keep it at 500 rad / min. Sequentially add 0.2 g of wetting and dispersing agent, 0.2 g of pH regulator, and 0.2 g of defoamer. After adding, adjust the stirring speed to 1500 rad / min and continue stirring for 15 min;

[0115] S2. While stirring, sequentially add 6 g of ammonium polyphosphate, 4 g of melamine, 14 g of titanium dioxide, and 2 g of talc powder into the container in order. Then add 5 g of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2000 rad / min and continue stirring for 45 min;

[0116] S3. While stirring, sequentially add 10 g of synergistic flame retardant and 0.8 g of viscosity reducer into the container in order. Then add 2.0 g of distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2500 rad / min and continue stirring for 10 min;

[0117] S4. Adjust the stirring speed to 800 rad / min, and continue to add 20 g of polyvinyl acetate emulsion, 8 g of water-soluble phenolic resin, 1.0 g of antifreeze, 2.2 g of film-forming aid, and 0.2 g of defoamer into the container, and stir for 8 min;

[0118] S5. Adjust the stirring speed to 500 rad / min, continue to add 4 g of high-silica fiber gel into the container, and continue stirring for 15 min after adding, then the finished product is obtained.

[0119] Comparative Example 1

[0120] An aqueous intumescent fireproof coating, whose composition is 20% polyvinyl acetate emulsion, 9% melamine, 22% ammonium polyphosphate, 8% pentaerythritol, 4% aluminosilicate fiber, 16% titanium dioxide, 0.5% dispersant, 0.4% defoamer, 0.1% preservative, and the balance is distilled water.

[0121] Comparative Example 2

[0122] An aqueous intumescent fireproof coating, whose composition is 25% styrene-acrylic emulsion, 12% melamine, 23% ammonium polyphosphate, 12% pentaerythritol, 8% titanium dioxide, 0.4% dispersant, 0.5% defoamer, 0.1% preservative, 0.2% thickener, and the balance is distilled water.

[0123] Test Example 2 Coating Basic Performance Test

[0124] The basic performance of the fireproof coatings of Examples 5 - 7 and Comparative Examples 1 - 2 was tested, and the results are shown in the following table.

[0125]

[0126] As can be seen from the above table, the fireproof coatings provided in Examples 5 - 7 have excellent basic physical and chemical properties, and the initial drying crack resistance is better than that of Comparative Example 1 and Comparative Example 2. At the same time, they have excellent storage stability. The viscosity change of the coating during 12 months of storage is small, and there is no delamination, precipitation, and hard sediment when the can is opened. While in Comparative Example 1, delamination occurred after 6 months of storage, and there was hard sediment, so the coating could not be used; in Comparative Example 2, delamination occurred after 8 months of storage, and there was more soft sediment, the measured viscosity increased significantly, and the construction performance was poor. The results show that the basic performance of the environmentally friendly aqueous intumescent fireproof coating developed by the present invention is excellent, and the storage stability of the fireproof coating has been greatly improved compared with the prior art.

[0127] Test Example 3 Fire Resistance Test

[0128] The fire resistance of the fireproof coatings of Examples 5 - 7 and Comparative Examples 1 - 2 was tested, and the results are shown in the following table.

[0129]

[0130]

[0131] As can be seen from the above table, for the fireproof coatings provided in Examples 5 to 7, the char layer is continuous, dense, hard and strong, with a high degree of expansion. Therefore, it has a relatively high fire resistance time. In Comparative Example 1, the char layer has large holes, is soft and easy to fall off, and has insufficient fire resistance. In Comparative Example 2, although the char layer is hard, it is loose and porous, and the expansion ratio is insufficient, resulting in insufficient fire resistance. This result shows that the Sa len-based polyphosphazene composite magnesium-aluminum layered double hydroxide synergistic flame retardant has a good flame retardant effect. When used in combination with a foaming agent and a dehydrating agent, it self-forms a flame retardant synergistic system. Without the need to add a charring agent, it further reduces the addition amounts of the foaming agent and the dehydrating agent, improves the flame retardant and fire resistance performance of the waterborne intumescent fireproof coating. When encountering fire, it expands and foams to form a continuous, uniform and dense expanded char layer, significantly improving the fire resistance performance of the fireproof coating compared with the prior art.

[0132] Test Example 4 Flame Retardant and Smoke Suppressant Performance Test

[0133] The flame retardant and smoke suppressant performance of the fireproof coatings of Examples 5-7 and Comparative Examples 1-2 was tested, and the results are shown in the following table.

[0134]

[0135] According to the ISO 5660 standard, a cone calorimeter was used to test the smoke suppressant performance of the fireproof coating. The specific test results are shown in the above table, and the test results were compared with the fireproof coatings of Comparative Example 1 and Comparative Example 2. The results show that for the fireproof coating of the present invention, the total heat release (THR) has decreased significantly compared with Comparative Example 1 and Comparative Example 2, and the flame retardant performance has been significantly improved. The average smoke production rate and the average total smoke production of Examples 5, 6, and 7 are 0.014 m 2 / S and 0.67 m 2 / m 2 , which are decreased by 26.3% and 58.6% respectively compared with Comparative Example 1, and decreased by 30% and 59.1% respectively compared with Comparative Example 2. The test results show that the fireproof coating of the present invention has been significantly improved in terms of flame retardant performance and smoke suppressant performance compared with the prior art.

[0136] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An environmentally friendly water-based intumescent fire retardant coating, characterized in that, It comprises raw materials in the following weight percentages: 20% - 30% film-forming substance, 2% - 5% foaming agent, 5% - 7% dehydrating agent, 10% - 15% synergistic flame retardant, 2% - 5% fiber gel, 16% - 20% pigment and filler, 3.5% - 5.0% auxiliary agent, and the balance is distilled water; The synergistic flame retardant is Salen-based polyphosphazene composite magnesium-aluminum layered double hydroxide; The Salen-based polyphosphazene composite magnesium-aluminum layered double hydroxide is prepared by the following method: (1) Take 2,4-dihydroxybenzaldehyde, o-phenylenediamine, hexachlorocyclotriphosphazene and triethylamine to react to obtain Salen-PZN, ultrasonically disperse it in distilled water to obtain a Salen-PZN suspension for standby; (2) Dissolve magnesium salt and aluminum salt in distilled water and then add them to the Salen-PZN suspension, and adjust the pH to 8 - 12 to obtain a suspension; (3) Put the suspension into a hydrothermal reaction kettle, heat it up to 80 - 180 °C for reaction, after the reaction ends, centrifuge at a speed of 8000 - 12000 r / min, freeze-dry for 24 - 48 h, and grind to obtain Salen-based polyphosphazene composite magnesium-aluminum layered double hydroxide.

2. The environmentally friendly water-based intumescent fireproof paint according to claim 1, wherein: In step (1), the preparation method of the Salen-PZN is as follows: A. Dissolve 2,4-dihydroxybenzaldehyde in organic solvent a to obtain solution a; B. Dissolve o-phenylenediamine in organic solvent a, and then slowly drop it into solution a to obtain solution b; C. React solution b at 10 - 40 °C for 8 - 24 h, filter, wash, and vacuum dry to obtain Salen-H6; D. Disperse Salen-H6 in organic solvent b to obtain solution c; E. Ultrasonically disperse hexachlorocyclotriphosphazene in organic solvent b, and then slowly drop it into solution c to obtain a mixture of Salen-H6 and hexachlorocyclotriphosphazene; F. Add triethylamine to the mixture, heat it up to 20 - 60 °C for reaction for 4 - 12 h, after the reaction stops, filter, wash, and vacuum dry to obtain Salen-PZN.

3. The environmentally friendly water-based intumescent fireproof coating according to claim 2, wherein: In steps A and B, the molar ratio of 2,4-dihydroxybenzaldehyde to o-phenylenediamine is (2.0 - 4.0):1; the organic solvent a is one of methanol, ethanol, pentaerythritol, dichloromethane, and chloroform.

4. The environment-friendly waterborne intumescent fireproof coating according to claim 3, characterized in that: In steps C - F, the molar ratio of Salen-H6 to hexachlorocyclotriphosphazene and triethylamine is (3 - 6):1:(8 - 10); In step C, the temperature of vacuum drying is 40 - 80 °C, and the time is 12 - 24 h; In steps D and E, the organic solvent b is one of methanol, ethanol, acetonitrile, tetrahydrofuran, and acetone; In step F, the temperature of vacuum drying is 60 - 100 °C, and the time is 12 - 24 h.

5. The environmentally friendly water-based intumescent fireproof paint according to claim 1, characterized in that: In step (1), the power of ultrasonic dispersion is 100 - 300 W, and the time is 5 - 10 min.

6. The environmentally friendly water-based intumescent fireproof paint according to claim 1, characterized in that: In step (2), the mass ratio of Salen-PZN to the magnesium salt and the aluminum salt is 1:(10 - 15):(5 - 8); the molar ratio of Mg 2+ in the magnesium salt to Al 3+ in the aluminum salt is (1 - 4):

1.

7. The environment-friendly waterborne intumescent fireproof coating according to claim 1, characterized in that: The film-forming substance is one or more of vinyl acetate emulsion, pure acrylic emulsion, acetate acrylic emulsion, water-soluble phenolic resin, styrene-acrylic emulsion, and silicone-acrylic emulsion, and the glass transition temperature of the film-forming substance is 35°C < Tg < 45°C; The dehydrating agent is ammonium polyphosphate and / or melamine phosphate, where the degree of polymerization of ammonium polyphosphate is > 1000; the foaming agent is one or more of melamine, dicyandiamide, and chlorinated paraffin; The pigment and filler include one or more of titanium dioxide, kaolin, aluminum hydroxide, magnesium hydroxide, and talc powder; The auxiliaries include one or more of wetting and dispersing agents, preservatives, defoaming agents, pH regulators, leveling agents, viscosity reducers, antifreeze agents, and film-forming aids.

8. The environmentally friendly water-based intumescent fireproof paint according to claim 1, wherein: The fiber gel is prepared from one or more of glass fiber, carbon fiber, aluminum silicate fiber, sepiolite fiber, alumina fiber, basalt fiber, and high-silica fiber, and the fiber diameter used is 5 - 8μm, and the aspect ratio is 20:1 - 25:1; The fiber gel is prepared by the following method: Divide distilled water into two parts, distilled water a and distilled water b, in a ratio of 4:

1. Preheat distilled water a to 60 - 65°C, adjust the stirring speed to 500 - 800 rad / min, add 3 wt% of silane-modified hydroxypropyl methylcellulose based on the total amount of distilled water, then add 1 wt% of Camine 328 auxiliary agent based on the total amount of distilled water, and keep stirring for 30 min. After the system shows a gel state, add distilled water b, slowly add 28 - 36 wt% of fiber, adjust the stirring speed to 800 - 1000 rad / min, and stir until the fiber is evenly dispersed in the gel to obtain the fiber gel.

9. A preparation method of the environment-friendly waterborne intumescent fireproof coating according to any one of claims 1-8, characterized in that, It includes the following steps: S1. Add part of the distilled water into a clean container, start stirring and keep it at 300 - 500 rad / min. Add the wetting and dispersing agent, pH value regulator, and part of the defoaming agent in sequence. After adding, adjust the stirring speed to 1500 - 1800 rad / min and continue stirring for 15 - 20 min; S2. Under the stirring state, continue to add the dehydrating agent, foaming agent, pigment and filler into the container in sequence, then add part of the distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2000 - 2500 rad / min and continue stirring for 45 - 60 min; S3. Under the stirring state, continue to add the synergistic flame retardant and viscosity reducer into the container in sequence, then add part of the distilled water to rinse the inner wall of the container and the stirring shaft. After adding, adjust the stirring speed to 2500 - 2800 rad / min and continue stirring for 10 - 15 min; S4. Adjust the stirring speed to 800 - 1000 rad / min, continue to add the film-forming substance, preservative, leveling agent, antifreeze agent, film-forming aid, and the remaining part of the defoaming agent into the container, and stir for 8 - 15 min; S5. Adjust the stirring speed to 500 - 800 rad / min, continue to add the fiber gel into the container, and continue stirring for 10 - 15 min after adding to obtain the finished product.

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