CN112961528A - Environment-friendly fireproof coating and preparation method thereof - Google Patents

Abstract

The invention discloses an environment-friendly fireproof coating and a preparation method thereof, and relates to the field of building coatings. The environment-friendly fireproof coating comprises the following raw materials in percentage by weight: the material comprises a high-molecular emulsion film former, an inorganic film former, an intumescent organic flame retardant, a non-intumescent inorganic heat-insulating filler, an intumescent inorganic heat-insulating filler, reinforcing fibers, a nano rare earth oxide, a coupling agent, a film-forming auxiliary agent, a dispersing agent, a thickening agent, a pH regulator, deionized water and the like; wherein the intumescent organic flame retardant is a cage-type macromolecular intumescent flame retardant containing N-P. The coating has excellent fireproof performance, stronger expansion times and fireproof performance, long fireproof time and excellent waterproof performance. The invention also discloses a preparation method of the environment-friendly fireproof coating.

Description

Environment-friendly fireproof coating and preparation method thereof

Technical Field

The invention relates to an environment-friendly fireproof coating and a preparation method thereof, and particularly discloses an intumescent fireproof coating which adopts an N-P cage-type macromolecular intumescent flame retardant as a fireproof functional group auxiliary agent.

Background

The fireproof coating is a functional coating, is widely applied to fireproof protection of steel structures, cables, ceilings, walls, tunnels, airplanes and other places, can protect flammable base materials, and retards rapid spread of fire.

The fire-retardant coating can be divided into inorganic fire-retardant coating and organic fire-retardant coating according to different base materials. The inorganic fireproof coating is mainly used for fireproofing by depending on the flame retardancy of the material, does not expand and foam, has light density, small heat conductivity and good fireproof performance, and can meet the fireproof requirement of 1-2h or even longer time according to different coating thicknesses. However, fire-retardant coatings made of pure inorganic materials are prone to be hard and brittle, and to crack and fall off. The organic fireproof coating can expand and foam to form a heat-insulating fireproof layer, has better physical and chemical properties, but has higher cost than the inorganic fireproof coating. The organic-inorganic composite high-performance fireproof coating has the characteristics of both machine type and inorganic type fireproof coatings, and not only is the improvement of the water resistance, impact resistance and artificial aging resistance of a coating film facilitated through the synergistic effect of the organic component and the inorganic component, but also the adhesive force of the coating film is improved, and the production cost of the coating is also facilitated to be reduced.

The common expansion type organic flame retardant system is a classic system of ammonium polyphosphate, melamine and pentaerythritol, the ammonium polyphosphate is used as a dehydration and carbonization catalyst, namely an acid source, and is very important for the fireproof performance of the fireproof coating, in terms of water resistance, domestic ammonium polyphosphate is influenced by the water solubility of the ammonium polyphosphate, is easy to absorb moisture, and foreign ammonium polyphosphate has good water resistance but high cost. And the ammonium polyphosphate is influenced by factors such as polymerization degree and pH value of the ammonium polyphosphate, so that the fireproof coating is easy to crack and collapse. In addition, in areas with large temperature difference, the use of ammonium polyphosphate with low polymerization degree can cause white powder to be precipitated on the surface of the coating, and the performance of the fireproof coating is influenced.

In the prior art, the fire-fighting material Limited, Chuanzhuoan, patent CN103113775A discloses an intumescent flame retardant containing N-P cage-shaped macromolecules and a preparation process thereof, the flame retardant effectively overcomes the defect that the traditional three-source material is non-uniform in dispersion, has high polymerization degree and water resistance, and can form a honeycomb-shaped compact carbon layer. On the basis, a great deal of research and development practices are carried out by the sea dragon nuclear material science and technology (Jiangsu) limited company, and an environment-friendly double-component high-temperature-resistant fireproof coating is disclosed in a patent CN104726017A, wherein the fireproof coating consists of A, B components, and the A component contains a hydroxyl silicone oil flame retardant, a magnetism-forming filler, a ceramic auxiliary agent and other heat-preservation and heat-insulation fillers; the component B contains a cross-linking agent, a coupling agent and a catalyst, and when the coating is used, the component A and the component B are mixed according to the mass ratio of 10:1, and the mixture is cured at 10-50 ℃ to form a film. Meanwhile, the company also provides a fireproof coating for a thick steel structure in CN104496499A, the coating consists of fireproof filler, a flame retardant, a main adhesive, an auxiliary adhesive, a waterproof agent and mica powder, the coating improves the adhesive property of the fireproof coating for the steel structure, optimizes the use amount of the flame retardant and ensures the long-term fireproof property of the fireproof coating for the thick steel structure; other additives such as a waterproof agent and the like are added, so that the water-resistant anti-permeability performance and the weather resistance of the steel structure fireproof coating are improved.

However, none of the above techniques relates to a thin fire retardant coating, and further, to the development and use of an aqueous thin fire retardant coating. The inventor uses the N-P containing cage-shaped macromolecule intumescent flame retardant in an aqueous thin fireproof coating taking aqueous emulsion as an adhesive to find that the water resistance of the coating is improved to a certain extent in a general formula, but the expansion ratio of an important parameter for evaluating the fireproof performance of the coating is different from that of a classic system of ammonium polyphosphate, melamine and pentaerythritol. Analysis suggests that the reason for the poor fire performance of the flame retardant may be the formation of pentaerythritol phosphate and eventually melamine pentaerythritol phosphate with phosphoric acid. Although the stability improvement of the flame retardant improves the water resistance of the fire retardant coating relative to polyphosphoric acid and ammonium polyphosphate, it also means that the reaction rate of the dehydration char-forming catalyst to generate acid such as phosphoric acid or phosphate ester upon combustion heating at high temperature of a fire is greatly reduced due to the stability of the flame retardant, so that the dehydration charring of the char-forming agent is affected by the shortage of the acid source. Through a large number of experiments, the applicant finds that the expansion ratio of the water-based thin fireproof coating is obviously improved by matching the flame retardant with the rare earth oxide, especially when the particle size of the rare earth oxide reaches the nanometer level. It is presumed that the oxide should have a catalytic action on the decomposition of the flame retardant, and the efficiency of forming phosphoric acid or phosphoric ester is improved.

Disclosure of Invention

The invention aims to provide an environment-friendly fireproof coating and a preparation method thereof, which are used for solving the problems that in the prior art, the stability of a flame retardant in the environment-friendly fireproof coating is improved, the waterproofness of the fireproof coating is improved, but the reaction rate of a dehydration and carbonization catalyst for generating acid such as phosphoric acid or phosphate ester during combustion and heating is greatly reduced at high temperature of a fire.

In order to solve the technical problems, the invention provides an environment-friendly fireproof coating which comprises the following raw materials in percentage by weight: 10-20% of high molecular emulsion film forming matter, 5-15% of inorganic film forming matter, 25-35% of intumescent organic flame retardant, 10-15% of non-intumescent inorganic heat-insulating filler, 2-8% of intumescent inorganic heat-insulating filler, 1-5% of reinforcing fiber, 0.2-0.8% of nano rare earth oxide, 0.5-1.5% of coupling agent, 1-3% of film forming auxiliary agent, 0.1-0.5% of dispersing agent, 0.1-0.5% of thickening agent, 0.1-0.5% of pH regulator and 10-30% of deionized water; wherein the intumescent organic flame retardant is a cage-type macromolecular intumescent flame retardant containing N-P.

Further, the polymer emulsion film forming matter is any one or more of styrene-acrylic emulsion, vinyl acetate-acrylic emulsion, pure acrylic emulsion and VAE emulsion.

Further, the inorganic film-forming material is silica sol and/or water glass.

Further, the coating also comprises 5-10 wt% of ammonium polyphosphate, and the polymerization degree of the ammonium polyphosphate is 600-750.

Further, the coupling agent is a silane coupling agent.

Further, the silane coupling agent is any one or more of KH540, KH550 and KH 560.

Further, the film forming aid is dodecyl alcohol and/or propylene glycol.

Further, the non-expansive type inorganic heat-insulating filler is any one or more of titanium dioxide, wollastonite powder, aluminum hydroxide, bentonite, zinc borate, silica micropowder and kaolin; the expanded inorganic heat-insulating filler is expandable graphite.

Furthermore, the reinforced fiber is any one or more of glass fiber, mineral fiber, carbon fiber and high silica fiber.

Further, the thickening agent is any one or more of hydroxypropyl methylcellulose, hydroxypropyl cellulose, methylcellulose, ethyl cellulose, hydroxyethyl cellulose, xanthan gum, guar gum, alkali-soluble thickening agent, hydrophobic modified non-polyurethane thickening agent, polymethyl pyrrolidone, fumed silica and organic bentonite.

Further, the N-P cage-type macromolecular intumescent flame retardant is prepared from the following raw materials in parts by weight: 20-60 parts of phosphoric acid; 10-30 parts of phosphorus pentoxide; 10-40 parts of pentaerythritol; 40-70 parts of melamine; the NKC-95-10 parts by weight, and the preparation process comprises the following steps:

a: adding the phosphoric acid and the phosphorus pentoxide in parts by weight into a reaction kettle, uniformly stirring, and heating to 100-150 ℃;

b: adding the pentaerythritol and the catalyst NKC-9 in parts by weight into a reaction kettle, and reacting for 600-720 min to obtain a pentaerythritol phosphate intermediate;

c: b, uniformly mixing the pentaerythritol phosphate intermediate obtained in the step B with the melamine in parts by weight, controlling the temperature range to be 180-280 ℃, curing at high temperature for 120-300 min, and crosslinking and curing to obtain pentaerythritol phosphate melamine salt;

d: and D, grinding the powder obtained in the step C to 200-400 meshes, and finally obtaining a finished product.

Further, the invention also provides a preparation method of the environment-friendly fireproof coating, which comprises the following steps:

(1) weighing the raw materials according to the proportion;

(2) mixing the coupling agent with the inorganic film forming matter, and standing for 24 hours; mixing the film-forming additive with the polymer emulsion film-forming material, and standing for 24 h;

(3) adding water, a dispersing agent and a non-expansive type inorganic heat-insulating filler into a stirrer, and uniformly stirring;

(4) adding the cage-type macromolecular intumescent flame retardant containing N-P into a high-speed dispersion machine, adding the mixture obtained by mixing and stirring in the step (3), dispersing at high speed, then placing the mixture into a nano-scale grinding machine, grinding until the particle size is below 50nm, starting the nano-scale grinding machine to cool circulating water during grinding, and keeping the grinding working temperature below 55 ℃;

(5) sequentially adding the inorganic film-forming material mixture, the polymer emulsion film-forming material mixture and the thickening agent which are mixed in the step (2) into the mixture obtained in the step (4), stirring uniformly while adding, and then adjusting the pH to 8-10 by using a pH regulator;

(6) adding the reinforced fiber material, the nano rare earth oxide and the intumescent inorganic heat-insulating filler in sequence, stirring uniformly while adding, dispersing uniformly, and filtering to obtain the finished product.

Further, in the step 6, after the intumescent inorganic heat insulation filler is added, a defoaming agent, ammonium polyphosphate and the like can be further added.

After the technical scheme is adopted, the invention at least has the following beneficial effects:

1. the invention adopts the matching use of the nanometer rare earth oxide and the existing cage-type macromolecular intumescent flame retardant containing N-P, improves the decomposition efficiency of the flame retardant, further improves the amount of acid substances during combustion, improves the catalytic performance, solves the problem of poor foaming performance of the flame retardant in the thin water-based fireproof coating, and obviously improves the fireproof performance.

2. According to the invention, ammonium polyphosphate with special polymerization degree is further added into the existing N-P containing cage-type macromolecular intumescent flame retardant, so that the problems of insufficient phosphorus content and low thermal decomposition efficiency of the N-P containing cage-type macromolecular intumescent flame retardant are solved while the water resistance of the water-based fireproof coating is not influenced.

3. According to the invention, organic film forming materials such as styrene-acrylic emulsion and vinyl acetate-acrylic emulsion and inorganic film forming materials such as silica sol are mixed to serve as film forming materials of the coating, so that the release of volatile organic matter content is reduced by reducing the using amount of the organic film forming materials while the excellent film forming property and adhesive force of the coating are ensured, and the coating is an environment-friendly product.

4. The invention adopts silica sol, water glass and the like as inorganic film forming materials, the main component of the inorganic film forming materials is amorphous silicon dioxide, after dehydration, colloidal particles are dehydrated and condensed into a rigid microporous silicon skeleton structure through hydroxyl, and the inorganic film forming materials have good physical properties such as compressive strength and high hardness; the skeleton structure has chemical inertness, no toxicity and good stability, so that the coating has excellent durability, weather resistance, chemical resistance, environmental protection and the like. The raw materials have wide sources and low price, and can reduce the production cost of the coating.

5. The invention adopts the N-P-containing cage-type macromolecular intumescent flame retardant which integrates three elements of a carbon source, an acid source and a gas source into a whole to form a porous carbon layer with a closed structure in the flame retardant process, plays the roles of heat insulation and oxygen isolation, can interrupt the combustion chain reaction and has good flame retardant property; in addition, the raw materials are nontoxic, have the function of smoke suppression in the combustion process, and can effectively prevent the phenomenon of molten drop; and the addition amount is 1/2-1/3 of a classical system, the addition amount is small, the use is convenient, and the production cost can be reduced.

6. According to the invention, expandable graphite is added into the organic-inorganic composite coating, and the two-dimensional lamellar structure of the graphite can be overlapped layer by layer in the coating to form a compact physical isolation layer, so that the flame retardant property is improved. The graphite can be crosslinked and compounded with emulsion in the coating to further form a layer of compact protective film, so that the air can be blocked, and the flame retardant effect can be achieved. The graphite generates a more compact and continuous carbon layer at high temperature, and the heat blocking effect is better. It produces carbon dioxide and water during combustion, which can act as an oxygen barrier.

7. The inorganic filler is ground to the nanometer level by adopting a nanometer-level grinding machine to obtain the nanometer filler with larger specific surface energy as the inorganic heat-insulating material, and the characteristics that the proportion of the surface atomic number of the inorganic nanometer filler is larger and the surface atomic number has unsaturated property are utilized to fill in the formed micropore silicon reticular structure and the formed carbon layer structure while the catalytic performance is improved, so that the micropore silicon reticular structure and the formed carbon layer structure have stronger compression resistance and hardness, the toughening can be obviously enhanced, and the adhesive force of the coating is obviously improved. The introduction of the nano particles enables the coating film to have the surface effect of the nano particles and form a shielding effect, thereby achieving the advantages of ageing resistance, difficult pulverization and the like.

8. The invention adds one or a mixture of more of glass fiber, mineral fiber and carbon fiber as the reinforcing fiber, which can effectively improve the strength of the coating, enhance the crack resistance and the high temperature resistance.

Detailed Description

The technical scheme of the invention is described in detail below with reference to specific examples, the raw materials of each example, the contents thereof by weight percentage, and the main performance indexes are listed in the following table 1, and the preparation method of the coating in each example is as follows: the method comprises the following steps:

(1) weighing the raw materials according to the proportion in the table 1;

(2) mixing the coupling agent with the inorganic film forming matter, and standing for 24 hours; mixing the film-forming additive with the polymer emulsion film-forming material, and standing for 24 h;

(3) adding water, a dispersing agent and a non-expansive type inorganic heat-insulating filler into a stirrer, and uniformly stirring;

(4) adding the cage-type macromolecular intumescent flame retardant containing N-P into a high-speed dispersion machine, adding the mixture obtained by mixing and stirring in the step (3), dispersing at a high speed of 1200r/m, placing the mixture into a nano-scale grinding machine, grinding until the particle size is below 50nm, starting the nano-scale grinding machine to cool circulating water during grinding, and keeping the grinding working temperature below 55 ℃;

(5) sequentially adding the inorganic film-forming material mixture, the polymer emulsion film-forming material mixture and the thickening agent which are mixed in the step (2) into the mixture obtained in the step (4), stirring uniformly while adding, and then adjusting the pH to 8-10 by using a pH regulator;

(6) adding the reinforced fiber material, the nano rare earth oxide, the intumescent inorganic heat-insulating filler, the ammonium polyphosphate and the defoaming agent in sequence, stirring uniformly while adding, dispersing uniformly, and filtering to obtain a finished product.

TABLE 1 raw materials of the examples, their contents in weight percent and their main performance indexes

Further, the following performance tests were also performed on examples 1 to 3 and comparative examples 1 to 3 in the present invention:

and (3) testing the water resistance of the coating:

the coating was applied to two 4 x 8 x 1.2cm steel plates, lane coated to a dry film of 1mm, and then placed in an oven at 40 ℃ for 7 days. Taking out, sealing with rosin paraffin, soaking in tap water tank, and observing after 24 hr.

And (3) testing the fireproof performance:

limit of fire test

According to the test of GB/14907-2018 standard, the test furnace temperature conforms to the temperature rise curve of GB/T9978, and the fire resistance limit is measured by the time when the back temperature of the Q235 steel plate reaches 538 ℃. The expansion factor is represented by the thickness of the fire retardant coating film after expansion/the thickness of the fire retardant coating film before expansion. The test results are shown in table 2.

TABLE 2 Water repellency and fire endurance, swell times test results

	Water-proof property	Limit of fire resistance/min	Expansion factor
				Example 1	No peeling and foam falling	98.3	48
Example 2	No peeling and foam falling	91.1	46
				Example 3	No peeling and foam falling	93.2	43
Comparative example 1	No peeling and foam falling	73.2	35
				Comparative example 2	No peeling and foam falling	75.1	37
Comparative example 3	No peeling and foam falling	79.2	38

As shown in Table 2, the flame retardant property of the fireproof coating added with the nano rare earth oxide and/or the ammonium polyphosphate with proper proportion is greatly improved.

In the foregoing description of embodiments, the particular features, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. An environment-friendly fireproof coating is characterized in that: comprises the following raw materials in percentage by weight: 10-20% of high molecular emulsion film forming matter, 5-15% of inorganic film forming matter, 25-35% of intumescent organic flame retardant, 10-15% of non-intumescent inorganic heat-insulating filler, 2-8% of intumescent inorganic heat-insulating filler, 1-5% of reinforcing fiber, 0.2-0.8% of nano rare earth oxide, 0.5-1.5% of coupling agent, 1-3% of film forming auxiliary agent, 0.1-0.5% of dispersing agent, 0.1-0.5% of thickening agent, 0.1-0.5% of pH regulator and 10-30% of deionized water; wherein the intumescent organic flame retardant is a cage-type macromolecular intumescent flame retardant containing N-P.

2. The environment-friendly fire retardant coating according to claim 1, characterized in that: the polymer emulsion film-forming material is any one or more of styrene-acrylic emulsion, vinyl acetate-acrylic emulsion, pure acrylic emulsion and VAE emulsion; the inorganic film-forming material is silica sol and/or water glass.

3. The environment-friendly fire retardant coating according to claim 1, characterized in that: also comprises 5-10 percent of ammonium polyphosphate by weight, and the polymerization degree of the ammonium polyphosphate is 600-750.

4. The environment-friendly fire retardant coating according to claim 1, characterized in that: the coupling agent is a silane coupling agent.

5. The environment-friendly fire retardant coating according to claim 4, characterized in that: the silane coupling agent is any one or more of KH540, KH550 and KH 560.

6. The environment-friendly fire retardant coating according to claim 1, characterized in that: the film forming aid is dodecyl alcohol and/or propylene glycol.

7. The environment-friendly fire retardant coating according to claim 1, characterized in that: the non-expansive inorganic heat-insulating filler is any one or more of titanium dioxide, wollastonite powder, aluminum hydroxide, bentonite, zinc borate, silica micropowder and kaolin; the expanded inorganic heat-insulating filler is expandable graphite.

8. The environment-friendly fire retardant coating according to claim 1, characterized in that: the reinforcing fiber is one or more of glass fiber, mineral fiber, carbon fiber and high silica fiber.

9. The environment-friendly fire retardant coating according to claim 1, characterized in that: the N-P cage-type macromolecular intumescent flame retardant is prepared from the following raw materials in parts by weight: 20-60 parts of phosphoric acid; 10-30 parts of phosphorus pentoxide; 10-40 parts of pentaerythritol; 40-70 parts of melamine; the NKC-95-10 parts by weight, and the preparation process comprises the following steps:

a: adding the phosphoric acid and the phosphorus pentoxide in parts by weight into a reaction kettle, uniformly stirring, and heating to 100-150 ℃;

b: adding the pentaerythritol and the catalyst NKC-9 in parts by weight into a reaction kettle, and reacting for 600-720 min to obtain a pentaerythritol phosphate intermediate;

c: b, uniformly mixing the pentaerythritol phosphate intermediate obtained in the step B with the melamine in parts by weight, controlling the temperature range to be 180-280 ℃, curing at high temperature for 120-300 min, and crosslinking and curing to obtain pentaerythritol phosphate melamine salt;

d: and D, grinding the powder obtained in the step C to 200-400 meshes, and finally obtaining a finished product.

10. A method for preparing the environment-friendly fire retardant coating according to any one of claims 1 to 9, characterized in that: the method comprises the following steps:

(1) weighing the raw materials according to the proportion;

(2) mixing the coupling agent with the inorganic film forming matter, and standing for 24 hours; mixing the film-forming additive with the polymer emulsion film-forming material, and standing for 24 h;

(3) adding water, a dispersing agent and a non-expansive type inorganic heat-insulating filler into a stirrer, and uniformly stirring;

(4) adding the cage-type macromolecular intumescent flame retardant containing N-P into a high-speed dispersion machine, adding the mixture obtained by mixing and stirring in the step (3), dispersing at high speed, then placing the mixture into a nano-scale grinding machine, grinding until the particle size is below 50nm, starting the nano-scale grinding machine to cool circulating water during grinding, and keeping the grinding working temperature below 55 ℃;

(5) sequentially adding the inorganic film-forming material mixture, the polymer emulsion film-forming material mixture and the thickening agent which are mixed in the step (2) into the mixture obtained in the step (4), stirring uniformly while adding, and then adjusting the pH to 8-10 by using a pH regulator;

(6) adding the reinforced fiber material, the nano rare earth oxide and the intumescent inorganic heat-insulating filler in sequence, stirring uniformly while adding, dispersing uniformly, and filtering to obtain the finished product.