Hydrophobic non-intumescent aerogel fireproof coating for steel structure and preparation method of hydrophobic non-intumescent aerogel fireproof coating

Abstract

The invention relates to the technical field of fireproof coatings, in particular to a hydrophobic non-intumescent aerogel fireproof coating for a steel structure and a preparation method of the hydrophobic non-intumescent aerogel fireproof coating. The hydrophobic non-intumescent aerogel fireproof coating for the steel structure comprises the following components in parts by weight: 5-25 parts of thermal insulation microspheres; 5-30 parts of inorganic fiber; 1-5 parts of ethylene glycol; 0.3 to 0.5 part of cellulose ether; 10 to 40 parts of inorganic resin; 0.3 to 1 part of a stabilizer; 0.5 to 1.5 parts of a thickening agent I; 0.1 to 0.6 part of a thickening agent II; 0.2 to 0.6 part of a bactericide; 0.1 to 0.5 part of a wetting agent; 0.3 to 0.6 part of a defoaming agent; 0.5-2 parts of a dispersant I; 30 to 50 parts of modified aerogel cement; and 15 to 40 parts of deionized water. The aerogel is subjected to hydrophobic modification to form a super-hydrophobic structure, so that collapse of the aerogel after water absorption is avoided, and the nano-porous structure of the aerogel is ensured.

Description

Technical Field

[0001] This invention relates to the field of fire-retardant coating technology, and in particular to a hydrophobic, non-expanding aerogel fire-retardant coating for steel structures and its preparation method. Background Technology

[0002] Steel structures are widely used in construction, bridges, and shipbuilding due to their high strength, light weight, and fast construction speed. However, steel structures have poor fire resistance; their strength drops rapidly in the event of a fire, leading to structural failure. Therefore, developing a highly efficient, environmentally friendly, and fire-resistant fire-retardant coating for steel structures is of significant practical importance.

[0003] In existing technologies, intumescent fire-retardant coatings can form a heat-insulating protective layer when a fire occurs, but their fire resistance and durability still need improvement. Non-intumescent fire-retardant coatings, on the other hand, do not expand when a fire occurs, but their heat insulation performance and workability are often inferior to those of intumescent coatings.

[0004] Traditional non-intumescent fire-retardant coatings commonly use materials such as cenospheres, vermiculite, and sepiolite fibers. These materials are generally inexpensive, but have high thermal conductivity, often requiring a very thick layer to meet fire resistance requirements. Furthermore, using cement as a base material frequently leads to issues like hollow areas and cracking during application. Therefore, there is a need to develop a new type of fire-retardant coating. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a hydrophobic non-expansive aerogel fireproof coating for steel structures and its preparation method.

[0006] To achieve the above objectives, the technical solution adopted is: One objective of this invention is to provide a hydrophobic, non-expanding aerogel fire-retardant coating for steel structures, comprising the following components by weight: 5-25 parts of heat-insulating microspheres 5-30 parts of inorganic fiber 1-5 parts of ethylene glycol 0.3 to 0.5 parts of cellulose ether 10-40 parts of inorganic resin stabilizer 0.3 to 1 part Thickener 0.5-1.5 parts Thickener 20.1-0.6 parts 0.2–0.6 parts of bactericide Wetting agent 0.1-0.5 parts Defoamer 0.3-0.6 parts Dispersant 0.5-2 parts 30-50 parts of modified aerogel paste 15-40 parts deionized water.

[0007] Preferably, the preparation method of the modified aerogel paste includes the following steps: S1: When preparing aerogels using the sol-gel method, methylsilicate is used as the silicon source and hexamethyldisiloxane (HMDZ) is used as the hydrophobic modifier to prepare hydrophobic SiO2 aerogels through supercritical drying. S2: Weigh 14.9g of the hydrophobic SiO2 aerogel powder from step S1, 85g of deionized water, and 0.1g of dispersant II. Disperse at high speed and mix thoroughly to obtain the modified aerogel slurry.

[0008] Preferably, the first thickener is inorganic bentonite SMY-LT, and the second thickener is modified polyurethane thickener DR299.

[0009] Preferably, the bactericide is at least one of chloromethylisothiazolinone, methylisothiazolinone, octylisothiazolinone, or benzisothiazolinone.

[0010] Preferably, the cellulose ether is hydroxyethyl cellulose ether.

[0011] Preferably, the defoamer is NXZ-A, the first dispersant is DA3500N, the second dispersant is OROTAN731A, and the wetting agent is DA202. The second objective of this invention is to provide a method for preparing the aforementioned hydrophobic, non-expanding aerogel fire-retardant coating for steel structures, comprising the following steps: (1) Add defoamer, dispersant I, wetting agent and cellulose ether to deionized water and disperse at high speed; (2) Add inorganic resin, ethylene glycol, stabilizer, and bactericide and stir evenly. Add thickener to adjust the viscosity of the system. (3) Add modified aerogel paste, inorganic fiber, heat insulation microsphere thickener II, disperse and stir evenly at high speed to obtain hydrophobic non-expansion aerogel fireproof coating.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses hexamethyldisiloxane to hydrophobically modify the aerogel. The contact angle of the aerogel after hexamethyldisiloxane modification is greatly improved, forming a superhydrophobic structure, which avoids the collapse of the aerogel after absorbing water and ensures the nanoporous structure of the aerogel.

[0013] This invention uses hydrophobically modified aerogel. The aerogel structure has a large number of pores. The air in the pores is a poor thermal conductor. Compared with steel structure, the thermal conductivity is lower. Under the same fire resistance conditions, it can significantly reduce the heat conduction to steel structure, thus playing a good protective role.

[0014] This invention utilizes hydrophobically modified aerogel, which has an extremely low thermal conductivity, requiring only a small amount for protection. This reduces the amount of coating material needed, decreases coating thickness, and facilitates application. The hydrophobically modified aerogel also exhibits excellent compatibility with inorganic resins, making the coating less prone to peeling and cracking, resulting in higher coating strength and greater stability. Attached Figure Description

[0015] Figure 1 This diagram illustrates the hydrophobicity improvement mechanism of hexamethyldisiloxane. Detailed Implementation

[0016] The present invention will be described below with reference to examples. These examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0017] Example 1 Preparation of modified aerogel slurry: In the preparation of aerogel using the sol-gel method, methylsilicate was used as the silicon source. Methylsilicate and methanol were mixed at a weight ratio of 1:0.84 and stirred for 9 minutes. The mixture was then added dropwise at a rate of 1.6 mL / min to an aqueous solution of 0.23 mol / L oxalic acid and 0.11 mol / L hydrochloric acid. After a water bath reaction for 2.5 hours, a sol solution was formed. Then, triethylamine (0.15 mol / L) was added as a catalyst, and the system slowly underwent a solution-gel transition, ultimately forming a network wet gel with Si-O-Si bonds as the backbone. Hexamethyldisiloxane (HMDZ, 11%) was used as a hydrophobic modifier to react with the silicic acid on the aerogel surface to form hydrophobic methyl groups, thereby preparing a hydrophobic SiO2 aerogel. The hydrogel was then dried using a supercritical drying system to prepare an aerogel powder suitable for coatings. Weigh 14.9g of modified aerogel powder, 85g of water, and 0.1g of OROTAN 731A, disperse them at high speed, and mix them evenly to obtain the modified aerogel slurry.

[0018] Add 30 parts deionized water, 0.4 parts cellulose ether, 0.3 parts DA3500N dispersant, 0.3 parts NXZ-A defoamer, and 0.4 parts DA202 wetting agent to a dispersion vessel and disperse at high speed for 20 minutes. Add 20 parts nano silica sol, 1 part potassium ion stabilizer, 0.1 part chloromethylisothiazolinone bactericide, 0.2 parts DR299 thickener, and 1 part ethylene glycol and disperse at high speed for 10 minutes. Add 30 parts modified aerogel slurry, 10 parts heat-insulating hollow glass microspheres, 10 parts aluminum silicate fiber, and 0.3 parts inorganic bentonite SMY-LT and stir evenly to obtain a hydrophobic non-expansive aerogel fireproof coating.

[0019] Example 2 Preparation of modified aerogel slurry: The modified aerogel powder was prepared in the same way as in Example 1. 19.9g of modified aerogel powder, 80g of water, and 0.1g of OROTAN 731A were weighed, dispersed at high speed, and mixed and stirred evenly to obtain modified aerogel slurry.

[0020] Add 30 parts deionized water, 0.4 parts cellulose ether, 0.3 parts DA3500N dispersant, 0.3 parts NXZ-A defoamer, and 0.4 parts DA202 wetting agent to a dispersion vessel and disperse at high speed for 20 minutes. Add 20 parts nano silica sol, 1 part potassium ion stabilizer, 0.1 part chloromethylisothiazolinone bactericide, 0.2 parts DR299 thickener, and 1 part ethylene glycol and disperse at high speed for 10 minutes. Add 40 parts modified aerogel slurry, 5 parts heat-insulating hollow glass microspheres, 5 parts aluminum silicate fiber, and 0.3 parts inorganic bentonite SMY-LT and stir evenly to obtain a hydrophobic non-expansive aerogel fireproof coating.

[0021] Example 3 Preparation of modified aerogel slurry: The modified aerogel powder was prepared in the same way as in Example 1. 24.9g of modified aerogel powder, 75g of water, and 0.1g of OROTAN 731A were weighed, dispersed at high speed, and mixed and stirred evenly to obtain modified aerogel slurry.

[0022] Add 30 parts deionized water, 0.4 parts cellulose ether, 0.3 parts DA3500N dispersant, 0.3 parts NXZ-A defoamer, and 0.4 parts DA202 wetting agent to a dispersion vessel and disperse at high speed for 20 minutes. Add 20 parts nano silica sol, 1 part potassium ion stabilizer, 0.1 part chloromethylisothiazolinone bactericide, 0.2 parts DR299 thickener, and 1 part ethylene glycol and disperse at high speed for 10 minutes. Add 45 parts modified aerogel slurry, 5 parts aluminum silicate fiber, and 0.3 parts inorganic bentonite SMY-LT and stir evenly to obtain a hydrophobic non-expansive aerogel fireproof coating.

[0023] Comparative Example 1 The difference from Example 1 is that the aerogel paste is not modified; Weigh 14.9g of aerogel powder, 85g of water, and 0.1g of DA3500N dispersant, disperse at high speed, and mix evenly to obtain aerogel slurry.

[0024] Add 30 parts deionized water, 0.4 parts cellulose ether, 0.3 parts DA3500N dispersant, 0.3 parts NXZ-A defoamer, and 0.4 parts DA202 wetting agent to a dispersion vessel and disperse at high speed for 20 minutes. Add 20 parts nano silica sol, 1 part potassium ion stabilizer, 0.1 part chloromethylisothiazolinone bactericide, 0.2 parts DR299 thickener, and 1 part ethylene glycol and disperse at high speed for 10 minutes. Add 30 parts aerogel slurry, 10 parts heat-insulating hollow glass microspheres, 10 parts aluminum silicate fiber, and 0.3 parts inorganic bentonite SMY-LT and stir evenly to obtain a hydrophobic non-expansive aerogel fireproof coating.

[0025] Comparative Example 2 The difference from Example 1 is that no modified aerogel slurry is added; Add 30 parts deionized water, 0.4 parts cellulose ether, 0.3 parts DA3500N dispersant, 0.3 parts NXZ-A defoamer, and 0.4 parts DA202 wetting agent to a dispersion vessel and disperse at high speed for 20 minutes. Add 20 parts nano silica sol, 1 part potassium ion stabilizer, 0.1 part chloromethylisothiazolinone bactericide, 0.2 parts DR299 thickener, and 1 part ethylene glycol and disperse at high speed for 10 minutes. Add 40 parts heat-insulating hollow glass microspheres, 10 parts aluminum silicate fiber, and 0.3 parts inorganic bentonite SMY-LT and stir evenly to obtain a hydrophobic non-expansive aerogel fireproof coating.

[0026] In the above-described method for preparing modified aerogel slurry, the hydrophobicity improvement mechanism of hexamethyldisiloxane is as follows: Figure 1 As shown.

[0027] The performance of the hydrophobic non-intumescent fire-retardant coatings prepared in Examples 1-3 and Comparative Examples 1-2 was tested in accordance with the relevant coating testing standards (GB14907-2018). The performance indicators are shown in Table 1. Table 1 Performance Indicators of the Test

[0028] As can be seen from the results in Table 1, the hydrophobic non-expansive aerogel fireproof coating prepared in the embodiments of the present invention has good flame retardant and fire-resistant properties and water resistance. The coating has high strength, good toughness, good anti-sagging and damp heat resistance.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydrophobic, non-expansive aerogel fireproof coating for steel structures, characterized in that, By weight, it includes the following components: 5-25 parts of heat-insulating microspheres 5-30 parts of inorganic fiber 1-5 parts of ethylene glycol 0.3 to 0.5 parts of cellulose ether 10-40 parts of inorganic resin stabilizer 0.3 to 1 part Thickener 0.5-1.5 parts Thickener 20.1-0.6 parts 0.2–0.6 parts of bactericide Wetting agent 0.1-0.5 parts Defoamer 0.3-0.6 parts Dispersant 0.5-2 parts 30-50 parts of modified aerogel paste 15-40 parts deionized water.

2. The hydrophobic, non-expansive aerogel fireproof coating for steel structures according to claim 1, characterized in that, The preparation method of the modified aerogel paste includes the following steps: S1: When preparing aerogels using the sol-gel method, hydrophobic SiO2 aerogels are prepared by supercritical drying, using methylsilicate as the silicon source and hexamethyldisiloxane as the hydrophobic modifier. S2: Weigh 14.9g of the hydrophobic SiO2 aerogel powder from step S1, 85g of deionized water, and 0.1g of dispersant II. Disperse at high speed and mix thoroughly to obtain the modified aerogel slurry.

3. The hydrophobic, non-expansive aerogel fireproof coating for steel structures according to claim 1, characterized in that, The first thickener is inorganic bentonite SMY-LT, and the second thickener is modified polyurethane thickener DR299.

4. The hydrophobic, non-expansive aerogel fireproof coating for steel structures according to claim 1, characterized in that, The bactericide is at least one of chloromethylisothiazolinone, methylisothiazolinone, octylisothiazolinone, or benzisothiazolinone.

5. The hydrophobic, non-expansive aerogel fireproof coating for steel structures according to claim 1, characterized in that, The cellulose ether is hydroxyethyl cellulose ether.

6. The hydrophobic, non-expansive aerogel fireproof coating for steel structures according to claim 2, characterized in that, The defoamer is NXZ-A, the first dispersant is DA3500N, the second dispersant is OROTAN 731A, and the wetting agent is DA202.

7. A method for preparing the hydrophobic, non-expansive aerogel fire-retardant coating for steel structures as described in claim 1, characterized in that, Includes the following steps: (1) Add defoamer, dispersant I, wetting agent and cellulose ether to deionized water and disperse at high speed; (2) Add inorganic resin, ethylene glycol, stabilizer, and bactericide and stir evenly. Add thickener to adjust the viscosity of the system. (3) Add modified aerogel paste, inorganic fiber, heat insulation microspheres and thickener II, and disperse and stir evenly at high speed to obtain hydrophobic non-expansion aerogel fireproof coating.

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