CN101914333B - Aqueous nano ultra-thin steel structure fireproof coating and preparation method thereof - Google Patents

Abstract

The invention discloses a water-based nano-ultra-thin steel structure fireproof coating and a preparation method thereof. The layered silicate nano-composite emulsion prepared by an in-situ emulsion polymerization method is used as a film-forming base material, and a fireproof and flame-retardant coating is added in a certain proportion. The dehydration charcoal catalyst, charcoal agent, foaming agent, filler, auxiliary agent and appropriate amount of water are fully ground and mixed. The content of each component (calculated as 100% by total weight) is: nanocomposite emulsion 35%-50%, dehydration carbon-forming catalyst 17.5%-23.5%, foaming agent 10%-15%, char-forming agent 5%-10% , dispersant 0.2% ~ 0.4%, defoamer 0.3% ~ 0.8%, stabilizer 0.3% ~ 0.6%, filler 0 ~ 2.0%, the balance is water. The invention can overcome the deficiencies of existing fireproof coatings for steel structures, and has the characteristics of excellent performance, easy availability of raw materials, low cost, and no pollution to the environment, and can form a uniform and stable expanded carbonized layer after being exposed to fire, thereby protecting the steel structure effect.

Description

A kind of water-based nano ultra-thin steel structure fireproof coating and preparation method thereof

technical field

The invention relates to a steel structure fireproof coating and a preparation method thereof, in particular to a water-based nanometer ultra-thin steel structure fireproof coating and a preparation method thereof, belonging to new materials in the coating field of the chemical industry.

Background technique

As the main form of modern architecture, steel structure is widely used by investors because of its light weight, high strength, good seismic performance, short construction period, high degree of industrialization of buildings, high space utilization rate, and investment saving. At this stage, steel structures are widely used in long-span and super-high buildings, but the characteristics of poor fire resistance of steel structures are also very obvious. Although steel is a non-combustible material, it is a good conductor of heat and can easily conduct heat. The critical temperature of the mechanical properties of steel is 540°C. And when a fire breaks out in a building, the temperature of the fire site can reach about 1000°C within a few minutes, and the exposed steel will soon rise above the critical temperature of 540°C, and its bearing capacity will drop sharply, causing the building to burn. collapse, resulting in huge property damage and serious casualties. Therefore, it is necessary to protect the steel structure from fire, and the use of fire-resistant coatings is an ideal protection method. The steel structure fire retardant paint is sprayed on the surface of the steel structure to protect it from fire and heat insulation, preventing the steel from rapidly heating up in a fire and reducing its strength, so as to gain time for firefighters to put out fires and save people.

Steel structure fire retardant coatings can be divided into thick type, thin type and ultra-thin type according to the classification method of thickness. In recent years, the application of light steel structures in engineering has been favored, and various light steel beams and grids can also be used for fire protection with this type of fire retardant coating. Due to the ultra-thin coating of this kind of fireproof coating, the amount of fireproof coating used in the project is greatly reduced compared with thick and thin steel structure, which not only reduces the total cost of the project, but also enables the steel structure to be effectively protected from fire. Promoted species.

At present, the ultra-thin steel structure fire retardant coating is widely used in domestic steel structure fire prevention. It is an intumescent coating, which is a research hotspot in recent years, and its usage accounts for almost 90% of all fire protection coatings. Intumescent fireproof coatings for steel structures are based on natural or synthetic polymers (usually resins or emulsions), filled with dehydration carbon-forming catalysts, carbon-forming agents, foaming agents, and supplemented by some inorganic seasonings and additives. It forms a coating with a thickness of 1.5mm to 3mm at room temperature, and expands and carbonizes in the event of a fire, forming a carbonized layer of 40 to 100mm, which plays a role in fire protection. Domestic coating products of this type are still mainly solvent-based with high VOC content, supplemented by ordinary water-based fire-resistant and flame-retardant coatings. Solvent-based fireproof coatings have the problems of releasing a large amount of organic solvents during production and construction, causing harm to the surrounding environment and production and construction personnel, and releasing a large amount of toxic gases during combustion. With the continuous improvement of environmental protection regulations, solvent-based coatings will be more and more restricted, and water-based fire-resistant coatings will gradually replace solvent-based coatings due to their environmental protection, safety, less pollution, convenient construction and low cost. However, ordinary water-based fire-resistant and flame-retardant coatings also have many deficiencies, mainly in: (1) poor fire-proof performance, poor coating strength after fire expansion, and will peel off, affecting fire-proof performance; (2) durability and aging resistance If the performance is not good, the bonding force between the coating and the substrate will gradually decrease, which will affect the fireproof performance; (3) There will be smoke safety problems in case of fire. Chinese patent CN 1974695A introduces a halogen-free low-smoke ultra-thin organic-inorganic composite fireproof coating, which is composed of high-temperature-resistant organic-inorganic nano-composite hybrid resin and organic resin, adding high-temperature resistant pigments and fillers, charring agents, and foaming agents , catalysts, additives and other components are obtained, the coating thickness is controllable at 0.2-2mm, and the fire resistance limit can reach 30-200min. Chinese patent CN 101205441A uses polyorganosiloxane and self-crosslinking polyacrylate composite emulsion as film-forming substances, and on the basis of commonly used ammonium polyphosphate, melamine and pentaerythritol as composite fire prevention additives, melamine phosphate is added And early foaming agent, the fire resistance limit of fire retardant coating can reach 90min (coating thickness 2mm).

Nanotechnology is being used more and more widely in coatings. It can greatly improve the optical properties and mechanical properties of the coating, and at the same time, it may also endow the coating with new functions, thereby improving the market competitiveness of coating products. Gan Chunfang et al. [Coating Industry, 2007, 10:15-18] added sodium-based montmorillonite to solvent-based intumescent fire retardant coatings, which can effectively improve the flame retardant performance of fire retardant coatings. Chinese patent CN 1346855A discloses a nano-composite high-temperature-resistant fireproof coating, which is composed of nano-silicon carbide, nano-silicate clay, phosphate, oxide and nano-aluminum silicate and other nano-particles with nano-organic polymer materials. Chinese patent CN 1712463A introduces an environment-friendly water-based nano-fire-proof and flame-retardant coating, which is composed of two nano-flame retardants and water-based resin, ammonium polyphosphate, melamine, char-forming agent, nano-color, filler, micron-color, filler and other Auxiliary compounds are obtained. But above-mentioned method all is to adopt blending method to prepare nano fireproof coating.

Contents of the invention

The present invention aims at the above-mentioned problems existing in the prior art, and provides a water-based nano-ultra-thin steel structure fireproof coating, which can overcome the deficiencies of the existing steel structure fireproof coatings, and has excellent performance, readily available raw materials, low cost, It has the characteristics of no pollution to the environment, and can form a uniform and stable expanded carbonization layer after being exposed to fire, thereby protecting the steel structure.

Another object of the present invention is to provide a method for preparing the above-mentioned water-based nanometer ultra-thin fireproof coating for steel structures.

In order to achieve the above-mentioned purpose of the present invention, a water-based nanometer ultra-thin steel structure fireproof coating of the present invention is realized by the following technical scheme.

A water-based nanometer ultra-thin steel structure fireproof coating of the present invention is prepared from the following components, and the content of each component (total weight is calculated as 100%) is:

Nano composite emulsion 35%～50%

Dehydration into charcoal catalyst

Foaming agent 10%～15%

Charging agent 5%～10%

Dispersant 0.2%～0.4%

Defoamer 0.3%～0.8%

Stabilizer 0.3%～0.6%

Filler 0～2.0%

Water Balance

The nano-composite emulsion is a sodium-based montmorillonite-modified acrylate nano-composite emulsion prepared by an in-situ emulsion polymerization method. The solid content of the nanocomposite emulsion is 25.0%-35.0%, and the content of montmorillonite is 0.5%-1.5%.

The dehydration char-forming catalyst is ammonium polyphosphate, the foaming agent is melamine, and the char-forming agent is pentaerythritol. Ammonium polyphosphate ammonium polyphosphate with a degree of polymerization DP>1000 is the best.

The dispersant is any one of sodium hexametaphosphate, sodium polyphosphate and sodium pyrophosphate.

The defoamer is one of tributyl phosphate, polymethyltriethoxysilane, methylpolysiloxane, and dimethylpolysiloxane.

The stabilizer is any one of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether and polyoxyethylene laurate.

The filler is any one or both of expandable graphite or organic bentonite.

The preparation method of a kind of water-based nano ultra-thin steel structure fireproof coating of the present invention is:

Weigh each component according to the ratio of raw materials, dissolve the dispersant and stabilizer in water, add 20%-50% of the content of the dehydration carbon-forming catalyst, char-forming agent, foaming agent, filler and the defoamer and stir Evenly, the slurry is obtained after being ground by a ball mill; add the slurry to the batching tank while stirring at a low speed, and at the same time add the nanocomposite emulsion as the base material and the rest of the defoamer in turn, the stirring speed is 200-400r/min, and continue to stir until the above materials Mix evenly and discharge to get the fireproof coating of this product.

Or, first weigh each component according to the ratio of raw materials, first dissolve the dispersant and stabilizer in water, then add the nanocomposite emulsion and defoamer, and add the dehydration carbon-forming catalyst, char-forming agent, foaming agent in turn under stirring. Agents and fillers, and then grind and mix evenly with a ball mill to get the fireproof coating of this product.

The ultra-thin steel structure fireproof coating belongs to the intumescent fireproof coating, and the film-forming material has a great influence on the performance of the intumescent fireproof coating. Under normal working conditions, it has excellent adhesion and improves the strength and barrier properties of the polymer matrix. It can also enhance the structure of the carbonized layer under the action of flame burning or high temperature, and make it a good insulator and mass transfer barrier, helping to form Carbonized layer with flame retardancy and excellent expansion and foaming effect.

Ammonium polyphosphate, as a catalyst for dehydration and carbonization, controls the thermal decomposition process of the coating, dehydrates the organic matter of the coating, forms a non-flammable carbonaceous three-dimensional grid structure, isolates the protected substrate and fire source, and reduces thermal decomposition The amount of flammable tars, aldehydes, and ketones produced; at the same time, water vapor is released to dilute the density of flammable gases and surrounding oxygen, preventing the occurrence of carbon oxidation reactions with large heat release. The invention adopts ammonium polyphosphate with a high degree of polymerization (DP>1000) as a dehydration and carbonization catalyst to avoid precipitation of the ammonium polyphosphate after being dissolved in water and reduce the fireproof performance of the paint.

As a carbon forming agent, pentaerythritol can be heated to form carbon alone or under the action of a dehydration carbon forming catalyst, so that the coating can form the material basis of a non-flammable three-dimensional foam carbonization layer at high temperature, and play a skeleton role in the foam carbonization layer.

As a foaming agent, melamine can decompose and release non-combustible gases when heated, such as ammonia, carbon dioxide, water vapor, etc. These non-combustible gases make the coating expand and form a spongy porous foam structure in the coating.

Expandable graphite or organic bentonite not only acts as a filler, but also has a synergistic effect on the fire resistance of the coating, and is added to the fire retardant coating as a flame retardant filler.

The defoamer can improve the leveling property of the fireproof coating, and eliminate shrinkage cavity, pinhole, sagging and other phenomena.

Dispersants effectively wet fillers and reduce the viscosity of high solids fillers.

Stabilizers can ensure the stability and storage stability of coatings during production.

The effect and benefit of the present invention is that the nano-composite emulsion prepared by in-situ emulsion polymerization is used as the film-forming base material, and the special lamellar structure of layered silicate can effectively improve the strength and barrier properties of the polymer matrix, and can be used in coating formulations. With the synergistic effect of medium and intumescent flame retardant system, a uniform foam layer with good mechanical properties can be formed under high temperature or flame, with good heat insulation, long flame resistance, smooth coating, and excellent water and weather resistance. In particular, the water-based fireproof coating prepared by the technology of the present invention uses water as a solvent, does not contain organic solvents and halogen flame retardants, has very low VOC content, produces little smoke in case of fire, and is non-toxic. It is an environmentally friendly technology. The preparation process of the invention is simple, low in cost and widely used.

Detailed ways

In order to further describe the present invention, a water-based nano ultra-thin steel structure fireproof coating and its preparation method of the present invention will be described in more detail below in conjunction with examples.

Example 1

According to the following listed components and content (percentage by weight, %), prepare steel structure fireproof coating of the present invention:

Nano composite emulsion 40

Ammonium polyphosphate 21.5

Melamine 12.9

Pentaerythritol 8.6

Sodium polyphosphate 0.3

OP-10 0.4

Tributyl phosphate 0.4

Water 15.9

The preparation method of this example is: dissolving OP-10 and sodium polyphosphate in water, adding ammonium polyphosphate, melamine, pentaerythritol and 1/2 tributyl phosphate, stirring evenly, and grinding by a ball mill to obtain a slurry. Add the slurry into the batching tank while stirring at a low speed, and at the same time add the nanocomposite emulsion and the remaining tributyl phosphate successively, the stirring speed is 200-400r/min, continue to stir until the above materials are mixed evenly, and the water-based nano super Fireproof coating for thin steel structures.

Example 2

According to the following listed components and content (percentage by weight, %), prepare steel structure fireproof coating of the present invention:

Nano composite emulsion 45

Ammonium polyphosphate 20.5

Melamine 12.3

Pentaerythritol 8.2

Sodium polyphosphate 0.4

OP-10 0.4

Tributyl phosphate 0.5

Expandable graphite 0.2

Water 12.5

The preparation method of this example is: dissolving OP-10 and sodium polyphosphate in water, adding ammonium polyphosphate, melamine, pentaerythritol and 1/2 tributyl phosphate, stirring evenly, and grinding by a ball mill to obtain a slurry. Add the slurry into the batching tank while stirring at a low speed, and at the same time add nanocomposite emulsion, expandable graphite and the remaining tributyl phosphate in sequence, the stirring speed is 200-400r/min, continue to stir until the above materials are mixed evenly, and the material is discharged to obtain the present invention Water-based nano ultra-thin steel structure fireproof coating.

Example 3

According to the following listed components and content (percentage by weight, %), prepare steel structure fireproof coating of the present invention:

Nano composite emulsion 48

Ammonium polyphosphate 21

Melamine 12.6

Pentaerythritol 8.4

Sodium polyphosphate 0.4

OP-10 0.6

Tributyl phosphate 0.5

Organic bentonite 1

Water 7.5

The preparation method of this example is: firstly weigh sodium polyphosphate, OP-10 and dissolve in water, then add nanocomposite emulsion and tributyl phosphate, add ammonium polyphosphate, pentaerythritol, melamine and organobentonite in sequence under stirring, After being ground and mixed uniformly by a ball mill, the water-based nano ultra-thin steel structure fireproof coating of the present invention is obtained after discharging.

Table 1 lists the components and contents (% by weight) of Examples 4-8 of the water-based nanometer ultra-thin fireproof coating for steel structures of the present invention.

Table 1 water-based nanometer ultra-thin steel structure fireproof coating composition and content (weight %)

In Table 1, the process steps of Example 46 are the same as Example 1, and the process steps of Examples 7-8 are the same as Example 3. When the coating prepared by the invention is used, the coating is uniformly coated on the surface of the treated substrate, and is naturally dried and solidified.

Claims (3)

1. an aqueous nano ultra-thin steel structure fireproof coating, is characterized in that being prepared from by following component, and each composition weight percentage composition is:

Described nano-composite emulsion is the sodium-based montmorillonite modification acrylate nano-composite emulsion of emulsion polymerization in situ preparation; Described carbonifying catalyst is ammonium polyphosphate, and whipping agent is trimeric cyanamide, and char-forming agent is tetramethylolmethane; Described dispersion agent is Sodium hexametaphosphate 99; Described defoamer is tributyl phosphate; Described stablizer is polyoxyethylene nonylphenol ether; Described filler is expansible black lead;

The solids content of described nano-composite emulsion is 25.0%～35.0%, and the content of polynite is 0.5%～1.5%.

2. the preparation method of a kind of aqueous nano ultra-thin steel structure fireproof coating as claimed in claim 1, it is characterized in that: take each component by proportioning raw materials, dispersion agent, stablizer are dissolved in water, add the 20%-50% in carbonifying catalyst, char-forming agent, whipping agent, filler and described antifoam content to stir, obtain slurry after ball mill grinding; Add successively nano-composite emulsion and all the other defoamers as base-material when slurry is added stirring at low speed in pill tank, stirring velocity is 200-400r/min, continues to be stirred to above mixing of materials even, and discharging namely gets the frie retardant coating of this product.

3. the preparation method of a kind of aqueous nano ultra-thin steel structure fireproof coating as claimed in claim 1, it is characterized in that: at first take each component by proportioning raw materials, first dispersion agent, stablizer are dissolved in water, then add nano-composite emulsion and defoamer, under agitation add successively carbonifying catalyst, char-forming agent, whipping agent and filler, more namely get the frie retardant coating of this product after ball mill grinding mixes.