Preparation method for carbon-nitrogen-sulfur-silicon environment-friendly steel structure expansion type fireproof coating

Abstract

Disclosed is a preparation method for a carbon-nitrogen-sulfur-silicon environment-friendly steel structure expansion type fireproof coating. The method comprises: under stirring, sequentially adding water, a dispersing agent, a defoaming agent, a coalescing agent, a preservative, urea gypsum and urea-formaldehyde resin; mixing evenly; under high-speed stirring, sequentially adding starch, vermiculite powder, graphite and basalt mineral powder to be evenly dispersed; adjusting the stirring speed, adding an emulsion, and evenly dispersing; adding a thickening agent, adjusting to a proper consistency, and mixing and dispersing evenly, so as to obtain a carbon-nitrogen-sulfur-silicon environment-friendly steel structure expansion type fireproof coating.

Description

Preparation method of carbon, nitrogen, sulfur and silicon environmentally friendly steel structure intumescent fire retardant coating Technical Field

[0001] The present invention belongs to the field of fire-retardant coatings for steel structures. It adopts raw materials such as starch, urea gypsum, formaldehyde-free urea-formaldehyde resin, aluminum silicate glass powder, vermiculite ore powder, and graphite ore powder to construct a new fire-retardant material system and prepare a new environmentally friendly fire-retardant coating for steel structures. The coating has good fireproof effect, significantly lower cost than traditional fire-retardant material systems, a wide range of raw material sources, convenient prices, a small amount of toxic gas released during combustion, and good market prospects.

[0002] The most direct, effective, and low-cost method for preventing steel structures from fire is to apply fire-retardant coatings to their surfaces. Fire-retardant coatings can block the transfer of heat to the steel surface, increasing the steel's fire resistance when heated, thereby achieving a fire-resistant effect. Fire-retardant coatings for steel structures primarily consist of a binder, a fire-retardant system, pigments, fillers, and other additives.

[0003] Binder, also known as film-forming agent, is the base material of intumescent fire-retardant coating. In addition to evenly dispersing the intumescent flame retardant system and filler to bond the coating into a whole, it can also participate in the carbonization process of the coating, decomposing at high temperature to form a carbon skeleton, playing an important role in the fire resistance of the fire-retardant coating.

[0004] Flame retardants, also known as flame retardants, are the primary component used in fire-retardant coatings, accounting for the largest proportion of their usage. Flame retardants generally include intumescent flame retardants, inorganic flame retardants, silicone flame retardants, and nanoparticle flame retardants. Intumescent flame retardants are the core component of intumescent fire-retardant coatings, primarily chemically reactive. The chemical reaction type mainly refers to the PCN system (i.e., polyammonium phosphate-pentaerythritol-melamine system), which is the most widely used system on the market. Ammonium polyphosphate is an acid source and catalyst, catalyzing the dehydration of the carbonizing agent into carbon, and decomposing it to produce non-flammable gases such as ammonia, water vapor, and carbon dioxide. Pentaerythritol is a carbon source, also known as a carbonizing agent, which is the basis of the intumescent flame retardant system. Under the action of the acid source at high temperature, the carbon source is dehydrated, thereby forming a dense insulating carbonized layer to protect the steel. Melamine is a gas source, also known as a foaming agent, and is an indispensable part of the intumescent flame retardant system. It can decompose at high temperatures to produce non-flammable gases such as ammonia, water vapor, and carbon dioxide, which promote the foaming and expansion of the carbonized layer into a honeycomb porous insulation layer. The decomposition temperatures of the foaming agent, catalyst, and carbonizing agent must match and coordinate with each other to achieve the best effect, so that the fire retardant coating expands into a sponge-like or foamy insulating carbon layer. The PCN system has been the primary system for intumescent fire retardant coatings for decades. This system also requires the addition of fillers such as titanium dioxide (titanium dioxide) to enhance the fire resistance of the foam layer. Physical intumescent materials, primarily expandable graphite, can also be added to the PCN system to improve its performance, but currently, few intumescent fire retardant coatings that depart from the PCN system and rely primarily on a physical foaming mechanism are available. Intumescent flame retardant systems are used in significant quantities in intumescent fire retardant coatings, typically accounting for 60-70% of the total coating weight. This contributes significantly to the cost, making low-cost, high-performance a key focus of fire retardant product development.

[0005] The applicant of this patent has been engaged in the production of fireproof materials and the construction of fireproof engineering for many years. The problems existing in the existing traditional PCN system are summarized as follows:

[0006] (1) Construction performance issues

[0007] Since the polymerization degree of ammonium polyphosphate is unstable in the coating system, it will affect the consistency of the product and thus the workability of the product. Generally, 5 to 7 coats are required for a 2 mm thick coating, which results in high construction costs and high project costs.

[0008] (2) Coating water resistance issues

[0009] Once the applied coating comes into contact with water, the PCN flame retardant system will be easily dissolved and consumed, the foaming performance of the coating will be greatly affected, and the fireproof performance will be greatly reduced;

[0010] (3) Environmental performance issues

[0011] Pentaerythritol, melamine, etc. will produce a large amount of toxic gas after burning, which has a pungent smell. In case of fire, the toxic emissions are large;

[0012] (4) Cost issues

[0013] The material cost of regular products that meet the standards is more than 20 yuan / kg, and the market price is around 50 yuan / kg. The high material cost and engineering cost have a great impact on their promotion in steel structure projects.

[0014] (5) Raw material source issues

[0015] Traditional system materials either use raw materials such as pentaerythritol and melamine, which are affected by international petrochemical prices, or use large amounts of ammonium polyphosphate, which consumes precious phosphorus resources and causes waste for the future agricultural fertilizer industry. Titanium dioxide is expensive and consumes too many resources. The overall resource consumption and costs are high, the raw material resources are not widely available, and are highly restricted. Summary of the Invention

[0016] The present invention aims to overcome the shortcomings of existing methods and provide a new type of carbon, nitrogen, sulfur, and silicon-based steel structure fire retardant coating with low cost, standardized raw material sources, low toxic gas emissions during combustion, good workability, and excellent fire resistance. The coating is made of starch, urea gypsum, formaldehyde-free urea-formaldehyde resin, vermiculite ore powder, and graphite ore powder to construct a new fireproof material system. In this technical system:

[0017] Starch is a renewable material and serves as a carbon source in this technology system. Under combustion conditions, as the flame-retardant gas isolates the oxygen in the air, the starch will be exposed to high temperatures, dehydrated and carbonized to become a carbon source.

[0018] The fireproof mechanism of urea gypsum is as follows: urea gypsum is a compound obtained by replacing the crystal water in gypsum with four molecules of urea (Formula 1). Differential thermal analysis shows that when urea gypsum is heated, the decomposition reaction shown in Formula 2 occurs at a temperature of 190-250°C, and the decomposition reaction shown in Formula 3 occurs at a temperature of 330-450°C, producing non-combustible gases such as carbon dioxide, ammonia, nitrogen, and water vapor, which can prevent air from entering, effectively dilute the oxygen in the air, and inhibit combustion, which is particularly beneficial to the oxygen-deficient carbonization of the coating. At the same time, the carbon layer expands during the release of the decomposition gas, and eventually the expanded carbon layer mixes with the residual calcium sulfate from the decomposition of the urea gypsum to form a new type of carbon-sulfur foaming layer. CaSO4·2H2O+4CO(NH2)2=CaSO4·4CO(NH2)2+2H2O (Formula 1) 3CaSO4·4CO(NH2)2=3CaSO4+2C3H6N6+6CO2+12NH3 (Formula 2) 2C3H6N6+9O2=6CO2+6N2+6H2O (Formula 3)

[0019] Formaldehyde-free urea-formaldehyde resin is an environmentally friendly resin that eliminates free formaldehyde. Its fireproof mechanism is:

[0020] Urea-formaldehyde resin is a product obtained by the polymerization reaction of urea and formaldehyde under the action of a catalyst (alkaline or acidic catalyst) (as shown in Formula 4). Differential thermal analysis shows that when the temperature is in the range of 65.0-260.0°C, the weight loss rate of urea-formaldehyde resin is 24.9%, which is the drying weight loss. Surface moisture and inherent moisture are released in this stage. The weight loss rate is the highest at 260.0-700.0°C, at 51.3%. Urea-formaldehyde resin undergoes thermal decomposition, that is, the molecular chain breaks to produce non-combustible gases such as carbon dioxide, ammonia, nitrogen, and water vapor, which provide a gas source and can prevent air from entering, effectively dilute the oxygen in the air, inhibit combustion, and facilitate the oxygen-deficient carbonization of the incompletely burned molecular chains of urea-formaldehyde resin, forming a dense carbon layer that provides a carbon source. The carbon layer expands during the release of the decomposition gas. Therefore, urea-formaldehyde resin can serve as a carbon source and gas source in the PCN expansion system.

[0021] nH2N-CO-NH2+nHCHO→H-[NH-CO-NH-CH2]-OH+(n-1)H2O (Formula 4)

[0022] Silicate composite glass powder is a high-temperature binder. Its fireproof mechanism is as follows: it partially melts under high temperature in the presence of fire, bonding the foaming material, increasing the mechanical properties of the foaming layer, stabilizing the foaming layer, and forming a dense glass body on the surface of the foaming layer, which blocks flames from entering the foaming layer and plays a fireproof role.

[0023] Vermiculite ore powder and graphite ore powder are both physical expansion materials. They will physically expand and foam when exposed to fire. Under the action of carbon layer and silicate composite glass binder, a stable foaming layer is formed. They have excellent high temperature resistance and play a main role in fire resistance.

[0024] The carbon, nitrogen, sulfur, and silicon in this technology are as follows: Carbon refers to the carbon source component in starch and urea-formaldehyde resin, which acts as a carbon layer, similar to the effect of pentaerythritol in traditional PCN systems. Graphite ore powder is a carbonaceous material and also contains carbon. Nitrogen refers to the nitrogen component in urea gypsum and urea-formaldehyde resin, which decomposes at high temperatures to produce nitrogen and ammonia gases, isolating the air and causing foaming, similar to the effect of melamine in traditional PCN systems. Sulfur refers to the sulfate in urea gypsum, which combines with the carbon layer at high temperatures to form a composite foam layer, enhancing fire resistance. Silicon refers to aluminum silicate glass, which acts as a high-temperature adhesive, similar to the effect of titanium pyrophosphate in traditional PCN systems. Vermiculite ore powder is also a silicate mineral and also contains silicon. This compounding results in a completely new fire-retardant coating system for steel structures. This technology system completely eliminates traditional PCN system materials, replacing the traditional system. This is a significant innovation that will significantly contribute to industry technological advancement, reduce project costs, and improve construction performance and the coating's water and fire resistance.

[0025] The present invention is to provide a method for preparing a carbon, nitrogen, sulfur and silicon environmentally friendly intumescent fire retardant coating for steel structures, which is characterized by comprising the following steps:

[0026] 1) Preparation method of carbon, nitrogen, sulfur and silicon environmentally friendly steel structure intumescent fire retardant coating

[0027] (1) Ingredients

[0028] The ingredients are prepared according to the following mass ratio: urea gypsum: urea-formaldehyde resin: water: dispersant: defoaming agent: film-forming aid: preservative: starch: vermiculite powder: graphite: aluminum silicate refractory powder (basalt aluminum silicate glass powder), aluminum silicate glass powder for construction or aluminum silicate basalt mineral powder (and other aluminum silicate materials, above 200 mesh): acrylic emulsion: thickener = 3-8: 6-15: 20-40: 0.3-1: 0.1-0.3: 0.5-1: 0.1-0.2: 2-8: 8-20: 2-10: 10-20: 8-30: 0.1-0.5.

[0029] (2) Preparation method

[0030] Add water, dispersant, defoaming agent, film-forming aid, preservative, urea gypsum, and urea-formaldehyde resin in sequence while stirring, and stir evenly. Add starch, vermiculite powder, graphite, and basalt mineral powder in sequence while stirring at high speed until dispersed evenly. Lower the stirring speed, add acrylic emulsion, disperse evenly, then add thickener, adjust to the appropriate consistency, stir and disperse evenly, and you can get carbon, nitrogen, sulfur, and silicon environmentally friendly steel structure intumescent fire retardant coating.

[0031] Compared with the traditional system, the present invention has the following technical features and advantages:

[0032] (1) Construction performance

[0033] Traditional system: Since the degree of polymerization of ammonium polyphosphate is unstable in the coating system, it will affect the consistency of the product and thus the workability of the product. Generally, 5 to 7 coats are required after 2 mm of coating, which results in high construction costs and high project costs.

[0034] This technical system: Due to the leveling and anti-shrinkage effects of urea gypsum, the thickness of this technical product can reach 1.5 mm in one-time construction. Generally, it only takes 2 times to reach the required thickness without sagging, which greatly saves construction labor costs and reduces project costs.

[0035] (2) Water resistance

[0036] Traditional system: Once the applied coating is soaked by water, its foaming performance will be greatly affected and its fireproof performance will be greatly reduced;

[0037] This technical system: The foaming performance is not affected by soaking and rain.

[0038] (3) Environmental performance

[0039] Traditional system: Pentaerythritol, melamine, etc. will produce a large amount of toxic gas after combustion, which has a pungent smell. In case of fire, the toxic emissions are large;

[0040] This technology system uses synthetically processed materials such as starch, urea, aluminum silicate minerals, graphite, and gypsum, which emit less toxic gases and harmful substances when burned.

[0041] (4) Cost advantage

[0042] Traditional system: The material cost of regular qualified products is more than 20 yuan / kg, and the market price is about 50 yuan / kg. The high material cost and project cost make it difficult for ordinary steel structure projects to be accepted by the market;

[0043] This acceptance system: The material cost is only 3-5 yuan / kg, which is much lower than the traditional system. It has strong market competitiveness and broad market prospects.

[0044] (5) Advantages of raw material sources

[0045] Traditional system materials either use raw materials such as pentaerythritol and melamine, which are affected by international petrochemical prices, or use large amounts of ammonium polyphosphate, which consumes precious phosphorus resources and causes waste for the future agricultural fertilizer industry. Titanium dioxide is expensive and consumes too many resources, resulting in high overall resource consumption and costs. Raw material resources are not widely available and are highly restricted.

[0046] This technology system uses synthetically processed materials such as starch, urea, aluminum silicate minerals, graphite, and gypsum. Starch is a renewable material with low cost. Urea comes from coal chemical industry and natural gas chemical industry. Domestic raw materials are abundant, the supply is large, and the price is low. Inorganic mineral materials such as aluminum silicate minerals, graphite, and gypsum have abundant domestic production, convenient prices, and can be obtained stably. They are not affected by international raw material fluctuations and have important application prospects.

[0047] Specific implementation methods

[0048] The examples given below are intended to further illustrate the present invention, but should not be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the contents of the above invention still fall within the scope of protection of the present invention.

[0049] Example 1:

[0050] A method for preparing a carbon, nitrogen, sulfur and silicon environmentally friendly intumescent fire retardant coating for steel structures, characterized by comprising the following steps:

[0051] 1) Preparation method of carbon, nitrogen, sulfur and silicon environmentally friendly steel structure intumescent fire retardant coating

[0052] (1) Ingredients

[0053] The ingredients are prepared in the following mass ratio: urea gypsum slurry: urea-formaldehyde resin: water: dispersant: defoaming agent: film-forming aid: preservative: starch: vermiculite powder: graphite: basalt aluminum silicate refractory powder (200 mesh): emulsion: thickener = 8:8:34:0.5:0.1:0.8:0.1:8:12:4:14:10:0.5

[0054] (2) Preparation method

[0055] While stirring, add water, dispersant, defoaming agent, film-forming aid, preservative, urea gypsum slurry, and urea-formaldehyde resin in sequence and stir evenly. While stirring at high speed, add starch, vermiculite powder, graphite, and basalt mineral powder in sequence until dispersed evenly. Lower the stirring speed, add acrylic emulsion, disperse evenly, then add thickener, adjust to the appropriate consistency, stir and disperse evenly, and you can get carbon, nitrogen, sulfur, and silicon environmentally friendly steel structure intumescent fire retardant coating.

[0056] Examples 2 to 4:

[0057] A method for preparing a carbon, nitrogen, sulfur and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the gypsum raw material in urea gypsum. The relevant parameters are shown in the following table:

[0058] Examples 5 to 9:

[0059] A method for preparing a carbon, nitrogen, sulfur and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, and the main step is to change the gypsum content in the urea gypsum. The relevant parameters are shown in the following table:

[0060] Embodiments 10-11:

[0061] A method for preparing a carbon, nitrogen, sulfur and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the raw material of aluminum silicate refractory powder. The relevant parameters are shown in the following table:

[0062] Examples 12 to 18:

[0063] A method for preparing a carbon, nitrogen, sulfur and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the grinding mesh size in the preparation method of aluminum silicate refractory powder. The relevant parameters are shown in the following table:

[0064] Examples 19 to 43:

[0065] A method for preparing a carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the mass percentages of the dispersant, defoamer, film-forming aid, preservative, and thickener in the preparation method of the carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The changed proportions are supplemented by water to 100%. The relevant parameters are shown in the following table:

[0066] Examples 44-53:

[0067] A method for preparing a carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the mass percentage of urea-formaldehyde resin in the preparation method of the carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The changed proportion is made up to 100% by water. The relevant parameters are shown in the following table:

[0068] Examples 54-60:

[0069] A method for preparing a carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the mass percentage of starch in the preparation method of the carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The changed proportion is made up to 100% by water. The relevant parameters are shown in the following table:

[0070] Examples 61 to 66:

[0071] A method for preparing a carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the mass percentage of aluminum silicate refractory powder in the preparation method of the carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The changed proportion is made up to 100% by water. The relevant parameters are shown in the following table:

[0072] Examples 67-73:

[0073] A method for preparing a carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the mass percentage of vermiculite ore powder in the preparation method of the carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The changed portion is made up to 100% by water. The relevant parameters are shown in the following table:

[0074] Examples 74-80:

[0075] A method for preparing a carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the mass percentage of graphite in the preparation method of the carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The changed portion is filled with water to 100%. The relevant parameters are shown in the following table:

[0076] Examples 81 to 87:

[0077] A method for preparing a carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The method steps are the same as those in Example 1, mainly changing the mass percentage of the emulsion in the preparation method of the carbon, nitrogen, sulfur, and silicon environmentally friendly intumescent fire retardant coating for steel structures. The changed proportion is made up to 100% by water. The relevant parameters are shown in the following table:

[0078] In the above embodiments, the percentages used are all by weight (mass) unless otherwise specified; the weights may be in grams or kilograms.

[0079] In the above embodiments, the process parameters in each step and the numerical values ​​of the amounts of each component are ranges, and any point can be applied.

[0080] The present invention is not limited to the above embodiments, and all of the contents of the present invention can be implemented and have the above good effects.

Claims

1. A method for preparing a carbon-nitrogen-sulfur-silicon environmentally friendly steel structure intumescent fire retardant coating, characterized in that The following steps are involved: 1) Preparation method of aluminum silicate refractory powder Aluminum silicate refractory powder can be obtained by grinding aluminum silicate materials such as basalt aluminum silicate glass powder, aluminum silicate glass powder for construction or aluminum silicate basalt mineral powder into powder to a size of more than 200 meshes. 2) Preparation method of carbon, nitrogen, sulfur and silicon environmentally friendly steel structure intumescent fire retardant coating (1) Ingredients The ingredients are prepared according to the mass ratio of urea gypsum: urea-formaldehyde resin: water: dispersant: defoaming agent: film-forming aid: preservative: starch: vermiculite powder: graphite: aluminum silicate refractory powder: emulsion: thickener = 3-8: 6-15: 20-40: 0.3-1: 0.1-0.3: 0.5-1: 0.1-0.2: 2-8: 8-20: 2-10: 10-20: 8-30: 0.1-0.

5. (2) Preparation method Add water, dispersant, defoaming agent, film-forming aid, preservative, urea gypsum and urea-formaldehyde resin in sequence while stirring, stir evenly, add starch, vermiculite powder, graphite and basalt mineral powder in sequence while stirring at high speed until dispersed evenly, lower the stirring speed, add acrylic emulsion, disperse evenly, then add thickener, adjust to suitable consistency, stir and disperse evenly, and you can get carbon, nitrogen, sulfur and silicon environmentally friendly steel structure intumescent fire retardant coating.

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