Environmentally friendly fire retardant coating for steel structure and preparation method thereof

Abstract

The present invention relates to the technical field of fire retardant coatings, and proposes an environmentally friendly fire retardant coating for steel structures and a preparation method thereof. The raw materials include the following components by weight: 40-90 parts polyacrylamide, 30-40 parts epoxy-terminated polybutadiene, 30-40 parts microencapsulated aluminum hydroxide, 10-20 parts carbonizing agent, 5-10 parts ammonium tripolyphosphate, and 5-10 parts foaming agent. The microencapsulated aluminum hydroxide comprises a wall material of polyisobutylene and a core material of aluminum hydroxide. This technical solution solves the problem of low bonding strength between steel structure fire retardant coatings and substrates in the prior art.

Description

Technical Field

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

[0002] Steel structures are widely used in the construction industry due to their high strength, good ductility, strong seismic resistance, and light weight. However, when ambient temperatures reach 300-400°C, steel structures can significantly deform and lose their load-bearing capacity, seriously impacting their reliability. Therefore, fire-retardant coatings are often applied to steel structures to improve their fire resistance.

[0003] Currently, fire-retardant coatings for steel structures have low bonding strength to the substrate, which results in easy detachment and seriously compromises the fire resistance of the steel structure. Furthermore, most existing fire-retardant coatings for steel structures contain halogen elements, which release toxic gases during combustion, negatively impacting the environment. Therefore, developing an environmentally friendly fire-retardant coating for steel structures with high bonding strength is of great significance. Summary of the Invention

[0004] The present invention provides an environmentally friendly fire retardant coating for steel structures and a preparation method thereof, which solves the problem of low bonding strength between the fire retardant coating for steel structures and a substrate in the related art.

[0005] The technical solutions of the present invention are as follows:

[0006] The present invention provides an environmentally friendly fire retardant coating for steel structures, wherein the raw materials include the following components in parts by weight: 40-90 parts of polyacrylamide, 30-40 parts of epoxy-terminated polybutadiene, 30-40 parts of microencapsulated aluminum hydroxide, 10-20 parts of a carbonizing agent, 5-10 parts of ammonium tripolyphosphate, and 5-10 parts of a foaming agent;

[0007] In the microencapsulated aluminum hydroxide, the wall material is polyisobutylene and the core material is aluminum hydroxide.

[0008] As a further technical solution, the preparation method of microencapsulated aluminum hydroxide comprises the following steps:

[0009] S1. dissolving polyisobutylene in n-hexane, mixing uniformly, adding aluminum hydroxide, and dispersing uniformly to obtain a mixed solution;

[0010] S2. Atomize and dry the mixed solution to obtain the microencapsulated aluminum hydroxide.

[0011] As a further technical solution, the mass ratio of the polyisobutylene to aluminum hydroxide is 1:4-2:3.

[0012] When the mass ratio of polyisobutylene to aluminum hydroxide is 1:4-2:3, the bonding strength of the steel structure fire retardant coating and the fire resistance of the steel structure can be further improved.

[0013] As a further technical solution, in step S2, the temperature during the atomization drying is 80-100°C.

[0014] As a further technical solution, the mass ratio of the polyacrylamide to the epoxy-terminated polybutadiene is 1.5-2:1.

[0015] As a further technical solution, the polyacrylamide includes a first polyacrylamide and a second polyacrylamide;

[0016] The molecular weight of the first polyacrylamide is 20,000-60,000;

[0017] The molecular weight of the second polyacrylamide is 100,000-200,000.

[0018] As a further technical solution, the mass ratio of the first polyacrylamide to the second polyacrylamide is 2-3:3-2.

[0019] When the mass ratio of the first polyacrylamide to the second polyacrylamide is 2-3:3-2, it helps to further improve the bonding strength of the steel structure fire retardant coating and the fire resistance of the steel structure.

[0020] As a further technical solution, the carbonizing agent is pentaerythritol and / or dipentaerythritol.

[0021] Carbonizing agents are beneficial in promoting the dehydration and carbonization of organic matter during combustion, thereby enhancing the fire resistance of steel structures.

[0022] As a further technical solution, the foaming agent is azobisisobutyronitrile and / or melamine.

[0023] The foaming agent helps to form an expansion layer during combustion, thereby enhancing the fire resistance of the steel structure.

[0024] The present invention also proposes a method for preparing the environmentally friendly steel structure fire retardant coating, comprising the following steps: uniformly mixing polyacrylamide and water, adding epoxy-terminated polybutadiene, microencapsulated aluminum hydroxide and other remaining components, and mixing them uniformly to obtain the steel structure fire retardant coating.

[0025] The working principle and beneficial effects of the present invention are:

[0026] 1. In the present invention, the steel structure fire retardant coating system uses environmentally friendly and low-toxic materials. Among them, the combined use of polyacrylamide and epoxy-terminated polybutadiene effectively improves the bonding strength of the steel structure fire retardant coating, thereby improving the fire resistance of the steel structure. In addition, by preparing microencapsulated aluminum hydroxide using polyisobutylene as the wall material and aluminum hydroxide as the core material, on the one hand, direct contact between aluminum hydroxide and polyacrylamide, which would cause the amide group of polyacrylamide to fall off, and on the other hand, the dispersion of aluminum hydroxide in the steel structure fire retardant coating is improved, and the uniformity of the fire retardant coating is enhanced, thereby improving the bonding strength of the steel structure fire retardant coating and further improving the fire resistance of the steel structure.

[0027] 2. In the present invention, by the coordinated use of two polyacrylamides with different molecular weights, the viscosity of the steel structure fire retardant coating is enhanced while the steel structure fire retardant coating has good fluidity, thereby further improving the bonding strength of the steel structure fire retardant coating and the fire resistance of the steel structure. DETAILED DESCRIPTION

[0028] 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 embodiments described 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 making any creative efforts are within the scope of protection of the present invention.

[0029] In the following examples and comparative examples, unless otherwise specified, the epoxy value of the epoxy-terminated polybutadiene is 0.5 mmol / g, the molecular weight of the polyisobutylene is 2400, the particle size of the aluminum hydroxide is 53 μm, the purity of pentaerythritol is 99%, the purity of ammonium tripolyphosphate is 99%, and the purity of azobisisobutyronitrile is 98%.

[0030] Example 1

[0031] A method for preparing an environmentally friendly fire-retardant coating for steel structures comprises the following steps: uniformly mixing, by weight, 40 parts of polyacrylamide (molecular weight 100,000) and 120 parts of water; adding 30 parts of epoxy-terminated polybutadiene, 30 parts of microencapsulated aluminum hydroxide, 10 parts of pentaerythritol, 5 parts of ammonium tripolyphosphate, and 5 parts of azobisisobutyronitrile; and uniformly mixing to obtain the fire-retardant coating for steel structures;

[0032] The preparation method of microencapsulated aluminum hydroxide comprises the following steps:

[0033] S1. Dissolve 15 parts of polyisobutylene in 30 parts of n-hexane, mix well, add 15 parts of aluminum hydroxide, and disperse evenly to obtain a mixed solution;

[0034] S2. Atomize and dry the mixed solution at 80° C. to obtain microencapsulated aluminum hydroxide.

[0035] Example 2

[0036] A method for preparing an environmentally friendly fire-retardant coating for steel structures comprises the following steps: uniformly mixing, by weight, 90 parts of polyacrylamide (molecular weight 100,000) and 270 parts of water; adding 40 parts of epoxy-terminated polybutadiene, 40 parts of microencapsulated aluminum hydroxide, 20 parts of pentaerythritol, 10 parts of ammonium tripolyphosphate, and 10 parts of azobisisobutyronitrile; and uniformly mixing to obtain the fire-retardant coating for steel structures;

[0037] The preparation method of microencapsulated aluminum hydroxide comprises the following steps:

[0038] S1. Dissolve 4 parts of polyisobutylene in 8 parts of n-hexane, mix well, add 36 parts of aluminum hydroxide, and disperse evenly to obtain a mixed solution;

[0039] S2. Atomize and dry the mixed solution at 100° C. to obtain microencapsulated aluminum hydroxide.

[0040] Example 3

[0041] The only difference between this embodiment and embodiment 2 is that, in this embodiment, when preparing microencapsulated aluminum hydroxide, the weight parts of polyisobutylene are 20 parts and the weight parts of aluminum hydroxide are 20 parts.

[0042] Example 4

[0043] The only difference between this embodiment and embodiment 2 is that, in this embodiment, when preparing microencapsulated aluminum hydroxide, the weight parts of polyisobutylene are 8 parts and the weight parts of aluminum hydroxide are 32 parts.

[0044] Example 5

[0045] The only difference between this embodiment and embodiment 2 is that, in this embodiment, when preparing microencapsulated aluminum hydroxide, the weight parts of polyisobutylene are 16 parts and the weight parts of aluminum hydroxide are 24 parts.

[0046] Example 6

[0047] The only difference between this embodiment and embodiment 4 is that in this embodiment, the weight parts of polyacrylamide are 80 parts.

[0048] Example 7

[0049] The only difference between this embodiment and embodiment 4 is that, in this embodiment, the weight proportion of polyacrylamide is 60 parts.

[0050] Example 8

[0051] The only difference between this embodiment and Example 6 is that in this embodiment, the polyacrylamide includes a first polyacrylamide (molecular weight of 40,000) and a second polyacrylamide (molecular weight of 150,000), wherein the weight proportion of the first polyacrylamide is 16 parts and the weight proportion of the second polyacrylamide is 64 parts.

[0052] Example 9

[0053] The only difference between this embodiment and embodiment 8 is that, in this embodiment, the weight proportion of the first polyacrylamide is 64 parts, and the weight proportion of the second polyacrylamide is 16 parts.

[0054] Example 10

[0055] The only difference between this embodiment and embodiment 8 is that in this embodiment, the weight proportion of the first polyacrylamide is 32 parts, and the weight proportion of the second polyacrylamide is 48 parts.

[0056] Example 11

[0057] The only difference between this embodiment and embodiment 8 is that, in this embodiment, the weight proportion of the first polyacrylamide is 48 parts, and the weight proportion of the second polyacrylamide is 32 parts.

[0058] Comparative Example 1

[0059] The only difference between this comparative example and Example 1 is that in this comparative example, no polyacrylamide is added, and the weight portion of the added epoxy-terminated polybutadiene is 70 parts.

[0060] Comparative Example 2

[0061] The only difference between this comparative example and Example 1 is that in this comparative example, no epoxy-terminated polybutadiene is added, and the weight portion of the added polyacrylamide is 70 parts.

[0062] Comparative Example 3

[0063] The only difference between this comparative example and Example 1 is that in this comparative example, the microencapsulated aluminum hydroxide is replaced by an equal amount of aluminum hydroxide.

[0064] The following performance tests were performed on the steel structure fire retardant coatings prepared in Examples 1-11 and Comparative Examples 1-3:

[0065] ① Bond strength: Tested in accordance with GB 14907-2018 "Fire Retardant Coatings for Steel Structures", with a load speed of 2000N / min;

[0066] ② Fire resistance limit: In accordance with GB 14907-2018 "Fire retardant coatings for steel structures", the test is carried out using the heating conditions of building fiber fires.

[0067] The test results are shown in Table 1 below.

[0068] Table 1 Test results of steel structure fire retardant coating performance

[0069]

[0070] Comparison of Example 1 with Comparative Examples 1-2 demonstrates that the combined use of polyacrylamide and epoxy-terminated polybutadiene effectively enhances the bonding strength of the fire-retardant coating for steel structures, thereby improving the fire resistance of the steel structure. Comparison of Example 1 with Comparative Example 3 demonstrates that the preparation of microencapsulated aluminum hydroxide using polyisobutylene as the wall material and aluminum hydroxide as the core material can enhance the bonding strength of the fire-retardant coating for steel structures and the fire resistance of the steel structure.

[0071] Comparison of Examples 2-3 with Examples 4-5 shows that when the mass ratio of polyisobutylene to aluminum hydroxide is 1:4-2:3, the bonding strength of the fire retardant coating for steel structures and the fire resistance of the steel structure can be further improved. Comparison of Example 4 with Examples 6-7 shows that when the mass ratio of polyacrylamide to epoxy-terminated polybutadiene is 1.5-2:1, the bonding strength of the fire retardant coating for steel structures and the fire resistance of the steel structure can be further improved. Comparison of Example 6 with Examples 8-11 shows that the coordinated use of two polyacrylamides with different molecular weights helps to further improve the bonding strength of the fire retardant coating for steel structures and the fire resistance of the steel structure. Comparison of Examples 10-11 with Examples 8-9 shows that when the mass ratio of the first polyacrylamide to the second polyacrylamide is 2-3:3-2, it helps to further improve the bonding strength of the fire retardant coating for steel structures and the fire resistance of the steel structure.

[0072] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An environmentally friendly fire retardant coating for steel structures, characterized in that: The raw materials include the following components in parts by weight: 40-90 parts of polyacrylamide, 30-40 parts of epoxy-terminated polybutadiene, 30-40 parts of microencapsulated aluminum hydroxide, 10-20 parts of a carbonizing agent, 5-10 parts of ammonium tripolyphosphate, and 5-10 parts of a foaming agent; In the microencapsulated aluminum hydroxide, the wall material is polyisobutylene and the core material is aluminum hydroxide; The polyacrylamide includes a first polyacrylamide and a second polyacrylamide; The molecular weight of the first polyacrylamide is 20,000-60,000; The molecular weight of the second polyacrylamide is 100,000-200,000; The mass ratio of the first polyacrylamide to the second polyacrylamide is 2-3:3-2.

2. The environmentally friendly fire retardant coating for steel structures according to claim 1, characterized in that: The preparation method of the microencapsulated aluminum hydroxide comprises the following steps: S1. dissolving polyisobutylene in n-hexane, mixing uniformly, adding aluminum hydroxide, and dispersing uniformly to obtain a mixed solution; S2. Atomize and dry the mixed solution to obtain the microencapsulated aluminum hydroxide.

3. The environmentally friendly fire retardant coating for steel structures according to claim 2, characterized in that: The mass ratio of the polyisobutylene to aluminum hydroxide is 1:4-2:

3.

4. The environmentally friendly fire retardant coating for steel structures according to claim 2, characterized in that: In step S2, the temperature during the atomization drying is 80-100°C.

5. The environmentally friendly fire retardant coating for steel structures according to claim 1, characterized in that: The mass ratio of the polyacrylamide to the epoxy-terminated polybutadiene is 1.5-2:

1.

6. The environmentally friendly fire retardant coating for steel structures according to claim 1, characterized in that: The carbonizing agent is pentaerythritol and / or dipentaerythritol.

7. The environmentally friendly fire retardant coating for steel structures according to claim 1, characterized in that: The foaming agent is azobisisobutyronitrile and / or melamine.

8. A method for preparing the environmentally friendly fire retardant coating for steel structures according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: uniformly mixing polyacrylamide and water, adding epoxy-terminated polybutadiene, microencapsulated aluminum hydroxide and other remaining components, and uniformly mixing to obtain a steel structure fire retardant coating.

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