A gypsum-based fire retardant coating for steel structure and its preparation method and application

Abstract

The present invention relates to the technical field of fire retardant coatings, and proposes a gypsum-based fire retardant coating for steel structures, a preparation method thereof, and an application thereof. The raw materials of the gypsum-based fire retardant coating include the following components in parts by weight: 150 parts of gypsum powder, 30-50 parts of perlite, 20-40 parts of ammonium polyphosphate, 2-6 parts of graphene oxide, 1-7 parts of aluminum sulfate, and 1-4 parts of aluminum chlorohydrate. Through the above technical scheme, the problems of low compressive strength and low bonding strength with steel structures of gypsum-based fire retardant coatings in related technologies are solved.

Description

Technical Field

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

[0002] With the rapid development of modern construction technology, steel structures are widely used in various types of buildings due to their advantages such as high strength, light weight and good earthquake resistance. However, steel structures have poor fire resistance in high temperature environments, and their strength and elastic modulus decrease with increasing temperature. Therefore, it is often necessary to apply fire retardant coatings on the surface of steel structures.

[0003] At present, most fire retardant coatings for steel structures are cement-based fire retardant coatings. Although they have good fireproof performance, they have problems such as high density, slow drying speed and easy cracking of the coating. Gypsum, as a common inorganic material, has the characteristics of light weight, heat insulation, fire resistance and wide source. Based on these characteristics, gypsum-based fire retardant coatings came into being. However, gypsum-based fire retardant coatings currently have the problems of low compressive strength and low bonding strength with steel structures, which limits their application in high stress bearing environments. Therefore, it is urgent to develop a gypsum-based fire retardant coating with high compressive strength and high bonding strength with steel structures. Summary of the invention

[0004] The present invention provides a gypsum-based fire retardant coating for steel structure and a preparation method and application thereof, which solves the problems of low compressive strength and low bonding strength with steel structure of the gypsum-based fire retardant coating in the related art.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a gypsum-based fire retardant coating for steel structures. The raw materials include the following components in parts by weight: 150 parts of gypsum powder, 30-50 parts of perlite, 20-40 parts of ammonium polyphosphate, 2-6 parts of graphene oxide, 1-7 parts of aluminum sulfate, and 1-4 parts of aluminum chlorohydrate.

[0007] As a further technical solution, the weight ratio of aluminum sulfate to aluminum chlorohydrate is 1.5~2:1.

[0008] In the present invention, when the weight ratio of aluminum sulfate to aluminum chlorohydrate is 1.5 to 2:1, the synergistic effect of the two can be further enhanced, thereby further improving the compressive strength of the gypsum-based fire retardant coating and the bonding strength with the steel structure.

[0009] As a further technical solution, the graphene oxide is modified graphene oxide, and the raw materials of the modified graphene oxide include a modifier and graphene oxide in a weight ratio of 1 to 6:100, and the modifier includes zinc p-hydroxybenzenesulfonate.

[0010] In the present invention, the inventors found that the use of zinc p-hydroxybenzenesulfonate modifier to modify graphene oxide can further improve the bonding strength between the gypsum-based fire retardant coating and the steel structure. It is speculated that the bonding effect between the gypsum-based fire retardant coating and the steel structure interface is mainly provided by the van der Waals force, and the graphene oxide modified by the modifier can increase the force between the interfaces, thereby further improving the bonding strength between the gypsum-based fire retardant coating and the steel structure.

[0011] As a further technical solution, the modifier further includes nickel sulfamate, and the weight of the zinc p-hydroxybenzenesulfonate is greater than the weight of the nickel sulfamate.

[0012] In the present invention, the inventors found that when the modifier for modifying graphene oxide also includes nickel sulfamate, the bonding strength between the gypsum-based fire retardant coating and the steel structure can be further improved through the synergistic modification of zinc p-hydroxybenzenesulfonate and nickel sulfamate, and when the weight of zinc p-hydroxybenzenesulfonate is greater than the weight of nickel sulfamate, the effect of improving the bonding strength is better.

[0013] As a further technical solution, the weight ratio of the zinc p-hydroxybenzenesulfonate to the nickel sulfamate is 4:1-2.

[0014] In the present invention, when the weight ratio of zinc p-hydroxybenzenesulfonate to nickel sulfamate is 4:1-2, the bonding strength between the gypsum-based fire retardant coating and the steel structure can be further improved.

[0015] As a further technical solution, the method for preparing the modified graphene oxide comprises the following steps:

[0016] S1, adding graphene oxide to a sodium hydroxide solution and dispersing it evenly to obtain a graphene oxide suspension;

[0017] S2. Dissolving the modifier in water to obtain a modified solution, adding the modified solution to the graphene oxide suspension, dispersing evenly, filtering, washing, and drying to obtain the modified graphene oxide.

[0018] As a further technical solution, the concentration of the sodium hydroxide solution is 0.05~0.1 mol / L.

[0019] As a further technical solution, the raw material further includes 1 to 2 parts of a water retaining agent, and the water retaining agent includes one or more of hydroxypropyl methylcellulose, carboxymethyl cellulose, and hydroxyethyl cellulose.

[0020] In the present invention, the addition of the water retaining agent can absorb and lock a large amount of water, maintain the humidity balance of the internal structure during the curing process, and avoid cracks caused by too fast drying. The water retaining agent is preferably carboxymethyl cellulose.

[0021] As a further technical solution, the raw materials also include 3 to 5 parts of a retarder, and the retarder includes one or more of sodium hexametaphosphate, sodium citrate, and potassium tartrate.

[0022] In the present invention, the addition of the retarder can prolong the setting time, so that the gypsum-based fire retardant coating can maintain good fluidity for a long time, which is convenient for construction workers to perform construction operations. The retarder is preferably potassium tartrate.

[0023] The present invention also provides a method for preparing the gypsum-based fire-retardant coating for steel structure, comprising the following steps: mixing the components evenly to obtain the gypsum-based fire-retardant coating.

[0024] The present invention also proposes the use of the gypsum-based fire retardant coating for steel structure or the gypsum-based fire retardant coating obtained by the preparation method in the field of steel structure fire protection.

[0025] As a further technical solution, the application includes the following steps: the gypsum-based fire retardant coating and water are evenly mixed in a weight ratio of 1 to 1.2:1, and sprayed on the surface of the steel structure.

[0026] As a further technical solution, during the spraying, the spraying thickness is 15~25mm.

[0027] The working principle and beneficial effects of the present invention are:

[0028] In the present invention, by rationally regulating the composition of the raw materials, the gypsum-based fire retardant coating has good fire resistance and significantly improves its compressive strength and bonding strength with the steel structure, wherein:

[0029] (1) Gypsum powder is used as a cementitious material to provide basic bonding and molding functions. When a fire occurs, the gypsum powder can dehydrate and absorb heat, slowing down the speed of heat transfer to the steel structure and providing a preliminary fire barrier for the steel structure;

[0030] (2) Perlite is lightweight. Its addition can reduce the additional load on the steel structure and prevent the cured coating from cracking and falling off, thus better maintaining the integrity of the coating.

[0031] (3) When ammonium polyphosphate is decomposed by heat, it releases non-combustible gas, which dilutes the concentration of combustible gas in the combustion area, reduces the intensity of combustion, and greatly blocks the transfer of heat to the steel structure;

[0032] (4) The two-dimensional layered graphene oxide can be stacked layer by layer in the gypsum-based fire retardant coating and fill the pores, making the structure denser, thereby significantly improving the compressive strength of the gypsum-based fire retardant coating;

[0033] (5) Aluminum sulfate and aluminum chloride can produce a synergistic effect. On the one hand, they can promote the formation of calcium sulfoxide, making the structure denser and improving the compressive strength. On the other hand, they can play a bridging adsorption role, improve the interface between gypsum-based fire retardant coatings and steel structures, and improve the bonding strength. DETAILED DESCRIPTION

[0034] 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.

[0035] In the following embodiments and comparative examples, unless otherwise specified, the model of gypsum powder is MH-16, purchased from Jingmen Leixin Gypsum Products Co., Ltd.; the median particle size of perlite is 2 mm; the degree of polymerization of ammonium polyphosphate is 1000; the model of graphene oxide is XFSG01; in aluminum chlorohydrate, the content of aluminum oxide is 46.05wt%, the content of chloride is 15.02wt%, and the basicity is 83%; the model of carboxymethyl cellulose is CM-52.

[0036] Example 1

[0037] A method for preparing a gypsum-based fire retardant coating for a steel structure comprises the following steps: by weight, 150 parts of gypsum powder, 30 parts of perlite, 20 parts of ammonium polyphosphate, 2 parts of graphene oxide, 1 part of aluminum sulfate, 1 part of aluminum chlorohydrate, 1 part of carboxymethyl cellulose and 3 parts of potassium tartrate are uniformly mixed to obtain a gypsum-based fire retardant coating.

[0038] Example 2

[0039] A method for preparing a gypsum-based fire retardant coating for a steel structure comprises the following steps: by weight, 150 parts of gypsum powder, 50 parts of perlite, 40 parts of ammonium polyphosphate, 6 parts of graphene oxide, 7 parts of aluminum sulfate, 4 parts of aluminum chlorohydrate, 2 parts of carboxymethyl cellulose and 5 parts of potassium tartrate are uniformly mixed to obtain a gypsum-based fire retardant coating.

[0040] Example 3

[0041] A method for preparing a gypsum-based fire-retardant coating for a steel structure comprises the following steps: by weight, 150 parts of gypsum powder, 40 parts of perlite, 30 parts of ammonium polyphosphate, 4 parts of graphene oxide, 4 parts of aluminum sulfate, 3.5 parts of aluminum chlorohydrate, 2 parts of carboxymethyl cellulose and 5 parts of potassium tartrate are mixed evenly to obtain a gypsum-based fire-retardant coating.

[0042] Example 4

[0043] The only difference between this embodiment and embodiment 3 is that in this embodiment, the weight portion of aluminum sulfate is 5.5 parts, and the weight portion of aluminum chlorohydrate is 2 parts.

[0044] Example 5

[0045] The only difference between this embodiment and embodiment 3 is that in this embodiment, the weight parts of aluminum sulfate are 4.5 parts and the weight parts of aluminum chlorohydrate are 3 parts.

[0046] Example 6

[0047] The only difference between this embodiment and embodiment 3 is that, in this embodiment, the weight parts of aluminum sulfate are 5 parts, and the weight parts of aluminum chlorohydrate are 2.5 parts.

[0048] Example 7

[0049] The difference between this embodiment and embodiment 6 is that in this embodiment, the graphene oxide is modified graphene oxide, and the preparation method of the modified graphene oxide is:

[0050] S1. Add 100 parts of graphene oxide to 1000 parts of a sodium hydroxide solution having a concentration of 0.05 mol / L, and perform ultrasonic vibration until the graphene oxide is uniformly dispersed to obtain a graphene oxide suspension;

[0051] S2. Dissolve 1 part of zinc p-hydroxybenzenesulfonate in 100 parts of water to obtain a modified solution, add the modified solution to the graphene oxide suspension, ultrasonically vibrate until it is evenly dispersed, filter, wash, and dry at 60° C. to obtain modified graphene oxide.

[0052] Example 8

[0053] The only difference between this embodiment and embodiment 7 is that in step S2 of this embodiment, the weight portion of zinc p-hydroxybenzenesulfonate is 6 parts.

[0054] Example 9

[0055] The only difference between this embodiment and embodiment 8 is that in step S2 of this embodiment, zinc p-hydroxybenzenesulfonate is replaced by an equal amount of nickel sulfamate.

[0056] Example 10

[0057] The difference between this embodiment and embodiment 9 is that in step S2 of this embodiment, 6 parts of zinc p-hydroxybenzenesulfonate are replaced by 2 parts of zinc p-hydroxybenzenesulfonate and 4 parts of nickel sulfamate.

[0058] Embodiment 11

[0059] The only difference between this embodiment and embodiment 9 is that in step S2 of this embodiment, 6 parts of zinc p-hydroxybenzenesulfonate are replaced by 3 parts of zinc p-hydroxybenzenesulfonate and 3 parts of nickel sulfamate.

[0060] Example 12

[0061] The only difference between this embodiment and embodiment 9 is that in step S2 of this embodiment, 6 parts of zinc p-hydroxybenzenesulfonate are replaced by 3.5 parts of zinc p-hydroxybenzenesulfonate and 2.5 parts of nickel sulfamate.

[0062] Embodiment 13

[0063] The only difference between this embodiment and embodiment 9 is that in step S2 of this embodiment, 6 parts of zinc p-hydroxybenzenesulfonate are replaced by 5 parts of zinc p-hydroxybenzenesulfonate and 1 part of nickel sulfamate.

[0064] Embodiment 14

[0065] The only difference between this embodiment and embodiment 9 is that in step S2 of this embodiment, 6 parts of zinc p-hydroxybenzenesulfonate are replaced by 4.8 parts of zinc p-hydroxybenzenesulfonate and 1.2 parts of nickel sulfamate.

[0066] Embodiment 15

[0067] The only difference between this embodiment and embodiment 9 is that in step S2 of this embodiment, 6 parts of zinc p-hydroxybenzenesulfonate are replaced by 4 parts of zinc p-hydroxybenzenesulfonate and 2 parts of nickel sulfamate.

[0068] Comparative Example 1

[0069] The only difference between this comparative example and Example 1 is that in this comparative example, no aluminum sulfate is added and the weight portion of aluminum chlorohydrate added is 2 parts.

[0070] Comparative Example 2

[0071] The only difference between this comparative example and Example 1 is that in this comparative example, no aluminum chlorohydrate is added, and the weight portion of aluminum sulfate added is 2 parts.

[0072] Comparative Example 3

[0073] The only difference between this comparative example and Example 1 is that in this comparative example, aluminum chlorohydrate and aluminum sulfate are not added.

[0074] Comparative Example 4

[0075] The only difference between this comparative example and Example 1 is that in this comparative example, graphene oxide is not added.

[0076] Experimental Example 1 Fire resistance test

[0077] The fire resistance of the gypsum-based fire retardant coatings prepared in Examples 1 to 15 was tested with reference to GB 14907-2018 "Fire Retardant Coatings for Steel Structures", wherein the gypsum-based fire retardant coatings were mixed uniformly with water at a weight ratio of 1.15:1 and sprayed on 400mm×400mm 36b hot-rolled I-beams (section modulus 126m -1 ) with a spraying thickness of 15 mm. After curing for 28 days, the test was conducted under the conditions of building fiber fire heating. The test results show that the fire resistance limits of the gypsum-based fire retardant coatings prepared in Examples 1 to 15 all exceed 3.00 h, which indicates that the gypsum-based fire retardant coatings of the present invention have good fire resistance.

[0078] Experimental Example 2 Compressive Strength Test

[0079] The compressive strength test of the gypsum-based fire retardant coatings prepared in Examples 1 to 6 and Comparative Examples 1 to 4 was carried out with reference to GB 14907-2018 "Fire Retardant Coatings for Steel Structures", wherein the gypsum-based fire retardant coatings and water were mixed evenly at a weight ratio of 1.15:1, injected into a test mold with a size of 70.7 mm × 70.7 mm × 70.7 mm, and after curing for 28 days, the compressive strength was tested at a loading speed of 150 N / min, and the results were retained to 2 decimal places. The test results are shown in Table 1 below.

[0080] Table 1 Compressive strength test results

[0081]

[0082] Comparison between Example 1 and Comparative Examples 1 to 3 shows that aluminum sulfate and aluminum chlorohydrate can produce a synergistic effect and significantly improve the compressive strength of the gypsum-based fire retardant coating. Comparison between Example 1 and Comparative Example 4 shows that the addition of graphene oxide can significantly improve the compressive strength of the gypsum-based fire retardant coating. Comparison between Examples 3 to 4 and Examples 5 to 6 shows that when the weight ratio of aluminum sulfate to aluminum chlorohydrate is 1.5 to 2:1, the compressive strength of the gypsum-based fire retardant coating can be further improved.

[0083] Experimental Example 3 Bond Strength Test

[0084] The bonding strength of the gypsum-based fire retardant coatings prepared in Examples 1 to 15 and Comparative Examples 1 to 3 was tested with reference to GB 14907-2018 "Fire Retardant Coatings for Steel Structures", wherein the gypsum-based fire retardant coatings were mixed evenly with water at a weight ratio of 1.15:1, sprayed on the surface of Q235B steel with a size of 70 mm × 70 mm × 6 mm, with a spraying thickness of 15 mm, and after curing for 28 days, the bonding strength was tested at a loading speed of 1500 N / min, and the results were retained to 2 decimal places. The test results are shown in Table 2 below.

[0085] Table 2 Bond strength test results

[0086]

[0087] The comparison between Example 1 and Comparative Examples 1 to 3 shows that aluminum sulfate and aluminum chlorohydrate can produce a synergistic effect, significantly improving the bonding strength between the gypsum-based fire retardant coating and the steel structure. The comparison between Examples 3 to 4 and Examples 5 to 6 shows that when the weight ratio of aluminum sulfate to aluminum chlorohydrate is 1.5 to 2: 1, the bonding strength between the gypsum-based fire retardant coating and the steel structure can be further improved. The comparison between Examples 6 and 7 to 8 shows that the use of a zinc p-hydroxybenzenesulfonate modifier to modify graphene oxide can further improve the bonding strength between the gypsum-based fire retardant coating and the steel structure. The comparison between Examples 8 to 9 and Examples 10 to 15 shows that the synergistic modification of graphene oxide by zinc p-hydroxybenzenesulfonate and nickel sulfamate can further improve the bonding strength between the gypsum-based fire retardant coating and the steel structure. The comparison between Examples 10 to 11 and Examples 12 to 15 shows that when the weight of zinc p-hydroxybenzenesulfonate is greater than the weight of nickel sulfamate, the bonding strength between the gypsum-based fire retardant coating and the steel structure can be further improved. Comparison of Examples 12-13 and Examples 14-15 shows that when the weight ratio of zinc p-hydroxybenzenesulfonate to nickel sulfamate is 4:1-2, the bonding strength between the gypsum-based fire retardant coating and the steel structure can be further improved.

[0088] The above are only preferred embodiments of the present invention and are 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 in the protection scope of the present invention.

Claims

1. A gypsum-based fire retardant coating for steel structure, characterized in that: The raw materials include the following components in parts by weight: 150 parts of gypsum powder, 30-50 parts of perlite, 20-40 parts of ammonium polyphosphate, 2-6 parts of graphene oxide, 1-7 parts of aluminum sulfate, and 1-4 parts of aluminum chlorohydrate; The graphene oxide is modified graphene oxide, the raw materials of the modified graphene oxide include a modifier and graphene oxide in a weight ratio of 1 to 6:100, the modifier includes zinc p-hydroxybenzenesulfonate, and the modifier also includes nickel sulfamate; The preparation method of the modified graphene oxide comprises the following steps: S1, adding graphene oxide to a sodium hydroxide solution and dispersing it evenly to obtain a graphene oxide suspension; S2. Dissolving the modifier in water to obtain a modified solution, adding the modified solution to the graphene oxide suspension, dispersing evenly, filtering, washing, and drying to obtain the modified graphene oxide.

2. A gypsum-based fire retardant coating for steel structure according to claim 1, characterized in that: The weight ratio of the aluminum sulfate to aluminum chlorohydrate is 1.5-2:

1.

3. A gypsum-based fire retardant coating for steel structure according to claim 1, characterized in that: The weight of the zinc p-hydroxybenzenesulfonate is greater than the weight of the nickel sulfamate.

4. A gypsum-based fire retardant coating for steel structure according to claim 3, characterized in that: The weight ratio of the zinc p-hydroxybenzenesulfonate to the nickel sulfamate is 4:1-2.

5. The gypsum-based fire retardant coating for steel structure according to claim 1, characterized in that: The raw materials further include 1-2 parts of a water retaining agent, wherein the water retaining agent includes one or more of hydroxypropyl methylcellulose, carboxymethyl cellulose, and hydroxyethyl cellulose; and / or The raw materials also include 3 to 5 parts of a retarder, and the retarder includes one or more of sodium hexametaphosphate, sodium citrate, and potassium tartrate.

6. The method for preparing a gypsum-based fire retardant coating for steel structure according to any one of claims 1 to 5, characterized in that: The following steps are involved: The components are mixed evenly to obtain the gypsum-based fire retardant coating.

7. Use of a gypsum-based fire retardant coating for steel structure according to any one of claims 1 to 5 or a gypsum-based fire retardant coating obtained by the preparation method according to claim 6 in the field of fire protection of steel structures.

8. The use according to claim 7, characterized in that: The method comprises the following steps: uniformly mixing the gypsum-based fire retardant coating and water in a weight ratio of 1-1.2:1, and spraying the mixture on the surface of the steel structure.

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