Light-color carbon-nitrogen-sulfur silicon steel structure fireproof coating and preparation method thereof

Abstract

The invention discloses a light-color carbon-nitrogen-sulfur silicon steel structure fireproof coating and a preparation method thereof. The fireproof coating is prepared by sequentially mixing basic raw materials, modified titanium dioxide, acrylic emulsion, a filling agent and graphite powder according to the mass ratio of 20: (2.5-20): (0-2): (0-27.52): (0.92-7.37). The modified titanium dioxide molecules can coat the surfaces of the graphite powder molecules to form a light-color fireproof coating; according to the preparation method, the KH550 and the titanium dioxide are subjected to a ball-milling reaction, so that the hydrophilic end of the KH550 is coupled and completely dispersed with the titanium dioxide, the titanium dioxide is modified, then the modified titanium dioxide is combined with the graphite, and the oleophylic end of the KH550 is coupled with the surface of a graphite molecule, so that the effect that the graphite is efficiently coated with the titanium dioxide is achieved, and the light-color carbon-nitrogen-sulfur silicon steel structure fireproof coating is prepared. The prepared fireproof coating is good in binding force, does not fall off in the processing and construction processes, and is high in construction efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of fire retardant coating preparation, and particularly relates to a light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coating and a preparation method thereof. Background Art

[0002] Steel structures are widely used in the construction industry due to their light weight and high strength. However, in a fire, their high thermal expansion coefficient and high thermal conductivity will lead to a complete loss of stiffness and strength, which can easily cause building collapse and endanger people's lives and property. Therefore, steel structures must be fire-protected. Among the current steel structure fire protection measures, applying fire-retardant coatings is the best solution for steel structure fire protection because of its good effect, low cost and easy construction. Steel structure fire retardant coatings are divided into intumescent and non-intumescent types. The components of intumescent steel structure fire retardant coatings work synergistically under high temperature, and the coating foaming thickness can increase to dozens of times of its original thickness, forming a stable, dense and low thermal conductivity carbonized layer to resist the fire source and achieve effective protection for the steel structure. The most widely used PCN system at present is the polyammonium polyphosphate-pentaerythritol-melamine system, in which ammonium polyphosphate acts as an acid source and catalyst, catalyzing the dehydration of the carbonizing agent to form a carbonized layer, and decomposing to produce flame-retardant gas; pentaerythritol is the carbon source, that is, the carbonizing agent, which is the basis of the intumescent flame retardant system. It dehydrates to form a carbonized layer covering the surface of the steel, and uses its own non-combustibility and thermal insulation properties to protect the steel; melamine is the gas source, that is, the foaming agent, which decomposes at high temperature to produce non-combustible gases such as ammonia, water vapor, and carbon dioxide, which dilutes the oxygen concentration, inhibits the combustion process, and is conducive to the expansion of the coating into a honeycomb-shaped carbonized layer. Since the decomposition temperatures of the acid source, carbon source and gas source in the PCN system are coordinated and consistent, the flame retardant system can achieve the best effect. Therefore, the PCN system has been the main system of fire retardant coatings in recent decades.

[0003] However, the traditional PCN system still has many problems: a) Since the degree of polymerization of ammonium polyphosphate is unstable in the coating system, it affects the consistency of the product and thus the construction performance of the product. Generally, 5 to 7 coats are required to apply 2mm thick paint, which is very expensive.

[0004] b) Due to the use of pentaerythritol and melamine, a large amount of toxic gases will be emitted in the event of a fire; the material cost and project cost are high, making it difficult to be accepted by the market.

[0005] c) Pentaerythritol and melamine in traditional system materials are affected by international petrochemical prices, and a large amount of ammonium polyphosphate is used, which consumes precious phosphorus resources and causes waste to the future agricultural fertilizer industry. The overall resource consumption and cost are high, the raw material resources are not widely available, and are highly restricted.

[0006] To address the issues with these traditional fire-retardant systems, we have disclosed a novel carbon-nitrogen-sulfur-silicon intumescent fire-retardant system for steel structures. We have filed for an invention patent (patent number CN202311668179.3). This system utilizes raw materials such as graphite ore powder, urea-formaldehyde resin, starch, urea gypsum, and aluminum silicate glass powder. The carbon in this flame-retardant system refers to the carbon source components in graphite, starch, and urea-formaldehyde resin, acting as a carbonizing agent, similar to the effect of pentaerythritol in traditional PCN systems. Nitrogen refers to the nitrogen components in urea gypsum and urea-formaldehyde resin, which decompose upon heating to produce refractory gases such as nitrogen and ammonia, insulating the air and expanding the carbon layer, similar to the effect of melamine in traditional PCN systems. Sulfur refers to the sulfate in urea gypsum, which, at high temperatures, forms a composite foaming layer with the carbon layer, enhancing fire resistance. Silicon refers to basalt ore powder and vermiculite, acting as a high-temperature binder, similar to the effect of titanium pyrophosphate in traditional PCN systems. This fire retardant coating flame retardant system is a new steel structure fire retardant coating system with low cost, wide source of raw materials, low toxic gas emissions during combustion, environmentally friendly, improved construction performance and coating water and fire resistance, excellent fire resistance, replacing the traditional system, and a major innovation.

[0007] However, a large amount of graphite powder is used in carbon-nitrogen-sulfur-silicon steel structure fire retardant coatings, and the color is gray-black, which cannot meet the market demand for white and light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coatings. White fillers such as titanium dioxide need to be added for color adjustment to obtain white and light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coatings.

[0008] However, the experiment found that the following problems exist in the preparation of white and light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coatings using this method: (1) In an aqueous system environment, the bonding force between titanium dioxide and super-hydrophobic graphite powder is weak, and it is easy to fall off during processing and use. It has poor stability and poor coating and covering ability, and corresponding technical methods are needed for improvement.

[0009] (2) The addition of titanium dioxide will affect the foaming stability of the coating. The foaming layer will become powdery and the surface will be loose and easily blown away. It is necessary to add corresponding materials to react with it to offset its negative impact.

[0010] (3) Since the addition of titanium dioxide and modified materials dilutes the graphite powder content in the system, affecting the expansion and foaming of the coating, it is necessary to make up the amount of diluted graphite powder to ensure the foaming thickness and fire resistance. Summary of the Invention

[0011] The present invention aims to provide a light-colored carbon-nitrogen-sulfur-silicon fire-retardant coating for steel structures and a preparation method thereof. The invention comprises the following steps: ball milling KH550 and titanium dioxide to couple the hydrophilic end of KH550 with the titanium dioxide and completely disperse the hydrophilic end; modifying the titanium dioxide; combining the modified titanium dioxide with graphite; and coupling the oleophilic end of KH550 with the surface of the graphite molecule, thereby achieving the effect of efficient coating of the graphite with the titanium dioxide. The light-colored carbon-nitrogen-sulfur-silicon fire-retardant coating for steel structures is prepared. The prepared fire-retardant coating has good bonding strength and does not fall off during processing and construction. The prepared fire-retardant coating can meet market demand for light-colored fire-retardant coatings and has good application prospects.

[0012] The present invention is achieved through the following technical solutions: A light-colored carbon-nitrogen-sulfur-silicon fire-retardant coating for steel structures is prepared by mixing basic raw materials, modified titanium dioxide, acrylic emulsion, filler, and graphite powder in a mass ratio of 20:2.5-20:0-2:0-27.52:0.92-7.37; the modified titanium dioxide molecules can be coated on the surface of the graphite powder molecules to form a light-colored fire-retardant coating; The basic raw materials are composed of urea gypsum, urea-formaldehyde resin, water, dispersant, defoaming agent, film-forming aid, preservative, starch, vermiculite powder, graphite, basalt mineral powder, acrylic emulsion and thickener, which are mixed in a mass ratio of 8:8:34:0.5:0.1:0.8:0.1:8:12:4:14:10:0.5.

[0013] Preferably, the modified titanium dioxide is prepared by mixing KH550 coupling agent, titanium dioxide and water in a mass ratio of 1-4:80:40-50, and then ball milling the mixture.

[0014] Preferably, the filler is ammonium polyphosphate; after combustion, the ammonium polyphosphate releases inert gas and dilutes oxygen, and the release of the inert gas helps the expansion and foaming of the fire retardant coating.

[0015] Preferably, the ammonium polyphosphate and titanium dioxide form titanium pyrophosphate at high temperature, and the titanium pyrophosphate is used to enhance the internal adhesion of the foaming layer to make the foaming more stable.

[0016] A method for preparing a light-colored carbon-nitrogen-sulfur-silicon fire-retardant coating for steel structures comprises the following steps: S1: prepare basic raw materials; S2: Preparation of modified titanium dioxide; S3: mixing the basic raw materials, modified titanium dioxide, acrylic emulsion, ammonium polyphosphate and graphite powder according to the above mass ratio to obtain a fire retardant coating.

[0017] Preferably, the specific operation method for configuring the basic raw materials is: adding water, dispersant, defoaming agent, film-forming aid, preservative, urea gypsum slurry, and urea-formaldehyde resin in sequence while stirring slowly in a stirring device, and stirring evenly; adding starch, vermiculite powder, graphite, and basalt mineral powder in sequence while stirring at high speed until they are evenly dispersed, reducing the stirring speed, adding acrylic emulsion, and dispersing evenly, then adding thickener, adjusting to a suitable consistency, and stirring and dispersing evenly to obtain a basic coating.

[0018] Preferably, the specific operation method for preparing the modified titanium dioxide is: taking KH550, titanium dioxide and water as raw materials, mixing KH550 coupling agent, titanium dioxide and water in a mass ratio of 1-4:80:40-50, and ball milling in a ball mill to obtain the modified titanium dioxide.

[0019] Preferably, the ball milling reaction time is 10 min-30 min when the ball mill is used for processing.

[0020] Preferably, the mechanism of the KH550 coupling agent modifying titanium dioxide is as follows: the hydrophilic end of the KH550 coupling agent is connected to the hydroxyl groups on the surface of the titanium dioxide, and the oleophilic end of the KH550 coupling agent is connected to the superhydrophobic graphite powder, thereby coating the titanium dioxide molecules on the surface of the graphite powder molecules to form a stable coating.

[0021] Preferably, in step S3, the basic raw materials are stirred, and during the stirring process, modified titanium dioxide, acrylic emulsion, ammonium polyphosphate and graphite powder are added in sequence.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1) In the present invention, KH550 is subjected to ball milling reaction with titanium dioxide, so that the hydrophilic end of KH550 is coupled with titanium dioxide and dispersed completely, the titanium dioxide is modified, and the modified titanium dioxide is combined with graphite, and the oleophilic end of KH550 is coupled with the surface of the graphite molecule, thereby achieving the effect of efficient coating of graphite by titanium dioxide, and preparing a light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coating. The prepared fire retardant coating has good bonding strength, does not fall off during processing and construction, and has high construction efficiency.

[0023] 2) In the present invention, the light-colored or white carbon-nitrogen-sulfur-silicon steel structure fire-retardant coating has good fire-proof effect, releases less toxic gas during combustion, is environmentally friendly, meets the market demand for light-colored or white fire-retardant coatings, and has good application prospects. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0025] Example 1: A light-colored carbon-nitrogen-sulfur-silicon fire-retardant coating for steel structures is prepared by modifying titanium dioxide so that it can be coated on the surface of graphite powder molecules. The modified titanium dioxide is prepared by mixing KH550 coupling agent, titanium dioxide, and water in a mass ratio of 1:80:40 and ball milling in a ball mill. Small grinding balls are taken at a ball-to-material weight ratio (the mass ratio of the material in the ball mill to the grinding balls) of 2-6 times and placed in the ball mill. The KH550 coupling agent, titanium dioxide, and water are then added to the ball mill and ball milled for 10-30 minutes to complete the reaction, thereby obtaining the modified titanium dioxide. The fire retardant coating is prepared by mixing basic raw materials, modified titanium dioxide and graphite powder in a mass ratio of 20:2.5:0.92; the modified titanium dioxide molecules can be firmly and stably coated on the surface of the graphite powder molecules to form a light-colored carbon, nitrogen, sulfur and silicon steel structure fire retardant coating; the basic raw materials are composed of urea gypsum, urea-formaldehyde resin, water, dispersant, defoaming agent, film-forming aid, preservative, starch, vermiculite powder, graphite, basalt mineral powder, acrylic emulsion and thickener, and the mass ratio of each component is 8:8:34:0.5:0.1:0 .8:0.1:8:12:4:14:10:0.5 mixing preparation; the preparation process is: while stirring in a stirring device at a slow speed, add water, dispersant, defoaming agent, film-forming aid, preservative, urea gypsum slurry and urea-formaldehyde resin in sequence according to the above proportions and stir evenly; while stirring at a 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 a suitable consistency, stir and disperse evenly to obtain a basic coating.

[0026] The mechanism of KH550 modified titanium dioxide is as follows: KH550 coupling agent is an amphiphilic coupling agent, the hydrophilic end of which is connected to the hydroxyl group on the surface of titanium dioxide, and the oleophilic end is connected to the superhydrophobic graphite powder, so that the titanium dioxide molecules can be coated on the surface of the graphite powder molecules to form a stable coating.

[0027] Examples 2-7 On the basis of Example 1, the ratio of KH550 to titanium dioxide in the modification process of titanium dioxide by KH550 coupling agent was changed. The relevant parameters are shown in the following table: Table 1: Mass ratio of KH550 to titanium dioxide By changing the ratio of KH550 to titanium dioxide, it was experimentally verified that the modified titanium dioxide molecules obtained by the mass ratio of Example 2 had a strong coating ability on the graphite powder molecules, and the coated body had a whiteness of 90%. The modified titanium dioxide molecules obtained in Example 7 had an extremely strong coating ability on the graphite powder molecules, and the coated body was white with a whiteness of 93%. It can be inferred that in Examples 2 to 7, as the KH550 content increased, the coating effect of the modified titanium dioxide molecules on the graphite powder molecules became better, and the coating color gradually became white.

[0028] Examples 8-12: On the basis of Example 1, the ratio of titanium dioxide to water in the process of titanium dioxide modification by KH550 coupling agent was changed. The relevant parameters are shown in the following table: Table 2: Mass ratio of titanium dioxide to water By changing the ratio of titanium dioxide to water, it was experimentally verified that the modified titanium dioxide prepared in Example 8 was thicker than the modified titanium dioxide prepared in Example 12, and had a better coating effect on the graphite powder molecules. It can be seen that as the mass ratio of water increased in Examples 8 to 12, the coating performance of the prepared titanium dioxide molecules on the graphite powder molecules showed a downward trend.

[0029] Examples 13-17: On the basis of Example 1, the weight ratio of the ball to material in the process of ball milling of KH550 modified titanium dioxide was changed. The relevant parameters are shown in the following table: Table 3: Ball-to-material weight ratio By changing the ball-to-material weight ratio, that is, the mass ratio of the material in the ball mill to the grinding balls, experiments have shown that the larger the ball-to-material mass ratio, the better the dispersibility of the modified titanium dioxide produced, which can improve the adhesion and weather resistance of the light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coating prepared from it.

[0030] Examples 18-26: On the basis of Example 1, the ball milling reaction time during the KH550 modified titanium dioxide process was changed. The relevant parameters are shown in the following table: Table 4: Ball milling reaction time By changing the ball milling reaction time, experiments have shown that the longer the ball milling time, the better the dispersibility of the modified titanium dioxide obtained, which can improve the adhesion and weather resistance of the light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coating prepared therefrom.

[0031] Examples 27-33: On the basis of Example 1, acrylic emulsion and ammonium polyphosphate were added, and the ratio of the base coating, modified titanium dioxide and graphite powder was changed; since the addition of modified titanium dioxide affected the foaming stability of the coating, and the graphite powder content was diluted and reduced, a certain amount of ammonium polyphosphate was required to offset its negative impact and make up for the diluted graphite powder content. Titanium dioxide is a very fine powdery substance. The fine powder is spread to every corner of the fireproof system, separating the binder from other components, so that it cannot play a good role in stabilizing the foaming layer. The foaming layer is powdered, and the surface is loose and easily Blow away. If added in large amounts, it will affect the foaming effect and foaming stability, which is not conducive to fire prevention. An appropriate amount of ammonium polyphosphate needs to be added to offset the negative impact of titanium dioxide. Ammonium polyphosphate not only acts as a gas source in the system, but also releases non-combustible gas during combustion, which can prevent air from entering, dilute oxygen, inhibit combustion, and release the gas produced by decomposition to the outside, which helps the expansion and foaming of the coating. At the same time, ammonium polyphosphate can react with TiO2 at high temperatures to form titanium pyrophosphate, which serves as the skeleton and adhesive of the system, enhances the internal adhesion of the foaming layer, and makes the foaming more stable. The chemical reaction formula is as follows: 2TiO2 + (NH4 )4P4O12 → 2TiP2O7 + 4NH3↑+2H2O↑ In addition, acrylic emulsion is added, which can enhance the film-forming properties of the coating.

[0032] Table 5: Mass ratio of each component in light-colored fire retardant coating By adjusting the mass ratio of each component in the light-colored fire-retardant coating, it has been verified through experiments that the more modified titanium dioxide is added, the lighter the color of the fire-retardant coating is, which can meet the market demand for fire-retardant coatings of different colors. In order to offset the impact of modified titanium dioxide on the foaming stability of the fire-retardant coating and ensure the construction performance and fire-retardant performance of the fire-retardant coating, the content of acrylic emulsion, ammonium polyphosphate and graphite powder can be supplemented and adjusted according to the mass ratio in Table 5.

[0033] In the above embodiments, the weight parts may be grams or kilograms.

[0034] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A light-colored carbon-nitrogen-sulfur-silicon fire retardant coating for steel structures, characterized in that: The fire retardant coating is prepared by mixing basic raw materials, modified titanium dioxide, acrylic emulsion, filler and graphite powder in a mass ratio of 20:2.5-20:0-2:0-27.52:0.92-7.37; the modified titanium dioxide molecules can be coated on the surface of the graphite powder molecules to form a light-colored fire retardant coating; The basic raw materials are composed of urea gypsum, urea-formaldehyde resin, water, dispersant, defoaming agent, film-forming aid, preservative, starch, vermiculite powder, graphite, basalt mineral powder, acrylic emulsion and thickener, which are mixed in a mass ratio of 8:8:34:0.5:0.1:0.8:0.1:8:12:4:14:10:0.

5.

2. The light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coating according to claim 1, characterized in that: The modified titanium dioxide is prepared by mixing a KH550 coupling agent, titanium dioxide and water in a mass ratio of 1-4:80:40-50, and then milling the mixture in a ball mill.

3. The light-colored carbon-nitrogen-sulfur-silicon fire retardant coating for steel structures according to claim 1, characterized in that: The filler is ammonium polyphosphate; after burning, the ammonium polyphosphate releases inert gas and dilutes oxygen, and the release of the inert gas helps the expansion and foaming of the fire retardant coating.

4. The light-colored carbon-nitrogen-sulfur-silicon steel structure fire retardant coating according to claim 3, characterized in that: The ammonium polyphosphate and titanium dioxide form titanium pyrophosphate at high temperature, and the titanium pyrophosphate is used to enhance the internal adhesion of the foaming layer and make the foaming more stable.

5. A method for preparing a light-colored carbon-nitrogen-sulfur-silicon fire-retardant coating for steel structures, characterized in that: The following steps are involved: S1: prepare basic raw materials; S2: Preparation of modified titanium dioxide; S3: mixing the basic raw materials, modified titanium dioxide, acrylic emulsion, ammonium polyphosphate and graphite powder according to the mass ratio described in claim 1 to obtain a fire retardant coating.

6. The method for preparing the light-colored carbon-nitrogen-sulfur-silicon fire retardant coating for steel structures according to claim 5, characterized in that: The specific operation method for preparing the basic raw materials is: adding water, dispersant, defoaming agent, film-forming aid, preservative, urea gypsum slurry, and urea-formaldehyde resin in sequence while stirring slowly in a stirring device, and stirring evenly; adding starch, vermiculite powder, graphite, and basalt mineral powder in sequence while stirring at high speed until they are evenly dispersed, reducing the stirring speed, adding acrylic emulsion, and dispersing evenly, then adding thickener, adjusting to a suitable consistency, and stirring and dispersing evenly to prepare a basic coating.

7. The method for preparing the light-colored carbon-nitrogen-sulfur-silicon fire retardant coating for steel structures according to claim 5, characterized in that: The specific operation method for preparing the modified titanium dioxide is: taking KH550, titanium dioxide and water as raw materials, mixing KH550 coupling agent, titanium dioxide and water according to a mass ratio of 1-4:80:40-50, and ball milling in a ball mill to obtain the modified titanium dioxide.

8. The method for preparing the light-colored carbon-nitrogen-sulfur-silicon fire retardant coating for steel structures according to claim 7, characterized in that: The ball milling reaction time is 10 min to 30 min when the ball mill is used for processing.

9. The method for preparing the light-colored carbon-nitrogen-sulfur-silicon fire retardant coating for steel structures according to claim 7, characterized in that: The mechanism of KH550 coupling agent modification of titanium dioxide is as follows: the hydrophilic end of KH550 coupling agent is connected to the hydroxyl group on the surface of titanium dioxide, and the oleophilic end of KH550 coupling agent is connected to the superhydrophobic graphite powder, so that the titanium dioxide molecules are coated on the surface of the graphite powder molecules to form a stable coating.

10. The method for preparing the light-colored carbon-nitrogen-sulfur-silicon fire retardant coating for steel structures according to claim 5, characterized in that: In step S3, the basic raw materials are stirred, and modified titanium dioxide, acrylic emulsion, ammonium polyphosphate and graphite powder are added in sequence during the stirring process.

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