Gypsum-based aerogel fireproof coating for steel structure

Abstract

The invention discloses a gypsum-based aerogel fireproof coating for a steel structure, and belongs to the technical field of fireproof coatings. The preparation method comprises the following steps: mixing 110-120 parts of gypsum base, 90-100 parts of water, 9-12 parts of inorganic filler, 2-4 parts of nano silicon dioxide aerogel and 1-3 parts of retarder, and fully stirring for 30 minutes to uniformly mix, thereby obtaining the gypsum-based aerogel fireproof coating. According to the gypsum-based aerogel fireproof coating disclosed by the invention, all the raw materials have a mutual synergistic effect, so that the gypsum-based aerogel fireproof coating has excellent comprehensive performance. Under the synergistic effect of the silicon dioxide aerogel and the hollow glass beads, the heat conductivity coefficient of the coating is effectively reduced, and the antifouling property and the corrosion resistance of the coating are enhanced; through the synergistic effect of magnesium hydroxide and graphene, the flame retardance, smoke suppression and wear resistance of the coating are enhanced; graphene and nano titanium dioxide have a synergistic effect, so that the weather resistance and the antibacterial property of the coating are enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of fire retardant coatings, and in particular relates to a gypsum-based aerogel fire retardant coating for steel structures. Background Art

[0002] Steel structure is one of the main structural types of modern buildings. It is widely used in large factories, stadiums, high-rise buildings, bridges, etc. due to its light weight and simple construction. However, steel structure building materials have unavoidable defects in fire prevention. Because the thermal conductivity of steel structure is high, the steel structure will heat up quickly when a fire occurs, which will cause its mechanical properties to drop sharply, resulting in building damage and collapse.

[0003] At present, steel structure fire retardant coatings are divided into two categories, organic expansion type and inorganic heat insulation type. Organic expansion type fire retardant coatings are easy to age and have poor weather resistance. The flame retardants contained in organic fire retardant coatings are mostly carbon-nitrogen-phosphorus or carbon-nitrogen-phosphorus-halogen systems, which contain substances such as melamine and chlorinated paraffin. These substances will quickly decompose and generate nitrogen dioxide, carbon monoxide and hydrogen chloride gases that are harmful to the human body after being exposed to high temperatures. These gases have a suffocating effect. This leads to the fact that during the fire, people are first exposed to toxic gases released by the expansion of the fire retardant coating due to heat, thereby increasing the number of casualties caused by building fires. At present, the traditional inorganic heat insulation type fire retardant coatings in China are mainly cement-based steel structure fire retardant coatings, gypsum-based steel structure fire retardant coatings and traditional non-expandable fire retardant coatings, most of which are made of cement, perlite, vermiculite and other materials. The fire retardant coatings themselves are heavy, the construction is cumbersome, and the construction cost is high. In addition, the cement itself is easy to crack after hydration, and the adhesion to the steel structure is relatively poor, and it is easy to fall off. Currently, the proportion of gypsum-based fire-retardant coatings in refractory materials is increasing.

[0004] In addition, steel structure fire retardant coatings may encounter mold growth during use, especially in humid and corrosive environments. Mold growth not only affects the appearance and protective properties of the coating, but may also cause further corrosion and damage to the steel structure, greatly shortening the service life of the steel structure fire retardant coating. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a gypsum-based aerogel fire retardant coating for steel structures.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A gypsum-based aerogel fire retardant coating for steel structures is prepared by the following steps:

[0008] The gypsum base, water, inorganic filler, silica aerogel and retarder are mixed, and stirred for 30 minutes to mix them evenly, so as to prepare the gypsum-based aerogel fire retardant coating.

[0009] Furthermore, the gypsum-based aerogel fire-retardant coating comprises the following raw materials in parts by weight: 110-120 parts of gypsum base, 90-100 parts of water, 9-12 parts of inorganic filler, 2-4 parts of nano-silicon dioxide aerogel, and 1-3 parts of retarder.

[0010] Furthermore, the gypsum is one or both of hemihydrate gypsum and natural gypsum.

[0011] Furthermore, the inorganic filler is a mixture of magnesium hydroxide, hollow glass microspheres, graphene, and nano-titanium dioxide in a mass ratio of 2:1:1:1.

[0012] When heated, magnesium hydroxide decomposes and absorbs the heat from the surface of the burning material, playing a flame retardant role; at the same time, it releases a large amount of water to dilute the oxygen on the surface of the combustible material, and the active magnesium oxide generated by the decomposition adheres to the surface of the combustible material, further preventing the combustion. During the entire flame retardant process, magnesium hydroxide not only does not produce any harmful substances, but the active magnesium oxide generated by its decomposition can also be a flame retardant and can also absorb the harmful gases and smoke generated by the combustion of a large number of polymer materials. The active magnesium oxide continuously absorbs the incompletely burned molten residues, which quickly stops the combustion, eliminates smoke, and prevents molten droplets.

[0013] Adding hollow glass microspheres to paint can not only improve the thermal insulation effect of the paint and reduce the cost of the paint, but also enhance the paint's impact resistance, anti-fouling and water-repellent properties and anti-corrosion properties.

[0014] Graphene has excellent mechanical properties. Adding it to fire-retardant coatings can improve the impact resistance and wear resistance of the coatings. Graphene can promote the formation of residual carbon during combustion, thereby preventing heat transfer. At the same time, graphene has a large surface area and can effectively adsorb flammable pyrolysis products. The oxygen-containing groups on its surface decompose and dehydrate at low temperatures, absorbing the surrounding heat and diluting the surrounding oxygen concentration, inhibiting combustion. In addition, graphene has antibacterial effects, and its antibacterial ability is based on the mixed synergistic effect of five mechanisms: physical cutting, membrane surface component extraction, physical capture, oxidative stress, and charge conduction.

[0015] Nano titanium dioxide has excellent UV shielding ability, can absorb and reflect ultraviolet rays, protect coatings from UV damage, and enhance the weather resistance of coatings. At the same time, nano titanium dioxide can kill bacteria, decompose harmful substances, and has antibacterial effects. In addition, nano titanium dioxide also has the effect of enhancing the scrub resistance of coatings.

[0016] Furthermore, the retarder is one or more of sodium polyphosphate, sodium hexametaphosphate, sodium citrate, potassium tartrate, potassium sodium tartrate, sodium gluconate, and calcium lignin sulfonate.

[0017] Beneficial effects of the present invention: The present invention enables the gypsum-based aerogel fire retardant coating to have excellent comprehensive performance through the mutual synergy between various raw materials. The synergy between silica aerogel and hollow glass microspheres effectively reduces the thermal conductivity of the coating and enhances the antifouling and anticorrosion properties of the coating; the synergy between magnesium hydroxide and graphene enhances the flame retardancy, smoke suppression and wear resistance of the coating; the synergy between graphene and nano-titanium dioxide enhances the weather resistance and antibacterial properties of the coating. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1

[0020] The preparation of gypsum-based aerogel fire retardant coating for steel structure is carried out in the following steps:

[0021] 110 parts of hemihydrate gypsum, 90 parts of water, 4 parts of magnesium hydroxide, 3.6 parts of hollow glass microspheres, 1.8 parts of graphene, 1.8 parts of nano-titanium dioxide, 1.8 parts of nano-silicon dioxide aerogel, and 1 part of sodium polyphosphate were mixed, and stirred for 30 minutes to mix evenly to prepare a gypsum-based aerogel fire retardant coating.

[0022] Example 2

[0023] The preparation of gypsum-based aerogel fire retardant coating for steel structure is carried out in the following steps:

[0024] Mix 65 parts of hemihydrate gypsum, 50 parts of natural gypsum, 96 parts of water, 4 parts of magnesium hydroxide, 2 parts of hollow glass microspheres, 2 parts of graphene, 2 parts of nano-titanium dioxide, 3 parts of nano-silicon dioxide aerogel, 1 part of sodium hexametaphosphate, and 1 part of potassium tartrate, and stir well for 30 minutes to mix evenly to prepare a gypsum-based aerogel fire retardant coating.

[0025] Example 3

[0026] The preparation of gypsum-based aerogel fire retardant coating for steel structure is carried out in the following steps:

[0027] 70 parts of hemihydrate gypsum, 50 parts of natural gypsum, 100 parts of water, 4.8 parts of magnesium hydroxide, 2.4 parts of hollow glass microspheres, 2.4 parts of graphene, 2.4 parts of nano-titanium dioxide in a mass ratio of 2:1:1:1, 4 parts of nano-silica aerogel, 1 part of sodium citrate, 1 part of sodium gluconate, and 1 part of calcium lignin sulfonate are mixed, and stirred for 30 minutes to mix evenly to prepare a gypsum-based aerogel fire retardant coating.

[0028] Comparative Example 1

[0029] The specific steps for preparing the coating are as follows:

[0030] The remaining steps remain unchanged, and the nano-silicon dioxide aerogel in Example 3 is removed to prepare the coating.

[0031] Comparative Example 2

[0032] The specific steps for preparing the coating are as follows:

[0033] The remaining steps remain unchanged, and the magnesium hydroxide, hollow glass microspheres, graphene, and nano-titanium dioxide in Example 3 are removed to prepare a coating.

[0034] Comparative Example 3

[0035] The remaining steps remain unchanged, and the nano-silica aerogel, magnesium hydroxide, hollow glass microspheres, graphene, and nano-titanium dioxide of Example 3 are removed to prepare a coating.

[0036] Performance Testing

[0037] The coatings prepared in Examples 1-3 and Comparative Examples 1-3 were coated on steel sheets, the coating thickness was controlled to be 2 cm, and the fire retardant coating was obtained after drying at room temperature for 72 hours. The thermal conductivity coefficient of the sample was measured by the steady-state method using a WNK-200D thermal conductivity tester produced by Nanjing Gaote Electronic Technology Co., Ltd. The test results are shown in Table 1 below:

[0038] Table 1

[0039]

[0040] The coatings of Examples 2-4 and Comparative Examples 1-2 were subjected to the following performance tests according to GB14907-2018 "Fire Retardant Coatings for Steel Structures", and the test results are shown in Table 2 below:

[0041] Table 2

[0042]

[0043] Antibacterial properties were tested in accordance with GB / T21866-2008 "Determination of antibacterial properties and antibacterial effects of antibacterial coatings (paint films)". The test results are shown in Table 3 below:

[0044] Table 3

[0045] Test items Anti-E. coli rate % Anti-Staphylococcus aureus rate % Example 2 98.78 98.76 Example 3 98.81 98.79 Example 4 98.84 98.82 Comparative Example 1 98.69 98.68 Comparative Example 2 78.56 78.47 Comparative Example 3 - -

[0046] “-” means no antibacterial property.

[0047] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0048] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A gypsum-based aerogel fire retardant coating for steel structures, characterized in that: Prepared by the following steps: The gypsum base, water, inorganic filler, silica aerogel and retarder are mixed, and stirred for 30 minutes to mix them evenly, so as to prepare the gypsum-based aerogel fire retardant coating.

2. The gypsum-based aerogel fire retardant coating for steel structure according to claim 1, characterized in that: The gypsum-based aerogel fireproof coating comprises the following raw materials in parts by weight: 110-120 parts of gypsum base, 90-100 parts of water, 9-12 parts of inorganic filler, 2-4 parts of nano silicon dioxide aerogel, and 1-3 parts of retarder.

3. The gypsum-based aerogel fire retardant coating for steel structure according to claim 1, characterized in that: The gypsum is one or both of semi-hydrated gypsum and natural gypsum.

4. The gypsum-based aerogel fire retardant coating for steel structure according to claim 1, characterized in that: The inorganic filler is a mixture of magnesium hydroxide, hollow glass microspheres, graphene and nano-titanium dioxide in a mass ratio of 2:1:1:

1.

5. The gypsum-based aerogel fire retardant coating for steel structure according to claim 1, characterized in that: The retarder is one or more of sodium polyphosphate, sodium hexametaphosphate, sodium citrate, potassium tartrate, potassium sodium tartrate, sodium gluconate, and calcium lignin sulfonate.

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