An inorganic non - expanding fire - retardant coating

Abstract

An inorganic non - expanding fire - retardant coating, characterized in that, by weight, its components include: 300 - 400 parts of cement, 150 - 250 parts of expanded vermiculite, 150 - 250 parts of expanded perlite, 50 - 150 parts of modified fiber, 100 - 200 parts of slag powder, 2 - 6 parts of cellulose, 8 - 13 parts of redispersible latex powder, 1 - 3 parts of polypropylene fiber, 10 - 30 parts of a fire - proof, heat - insulating and flame - retardant agent with water - absorption and expansion properties, and 30 - 50 parts of additives. This fire - retardant coating has the characteristics of environmental protection, low cost and excellent fire - proof performance.

Description

Technical Field

[0001] The present invention relates to the technical field of steel structure fireproof coatings, and specifically to an inorganic non-expansive fireproof coating, which is a non-expansive fireproof coating based on a cement binder. Background Art

[0002] The development of economy and society has promoted the development of the construction industry. Large buildings such as exhibition halls, airport terminals, large shopping malls, stadiums, high-class hotels, and industrial factories are increasing continuously, and are developing towards being large and beautiful. Most of their main load-bearing members are steel structures.

[0003] Therefore, the fire protection of steel structures has attracted more and more attention. Although steel belongs to non-combustible materials, its fire resistance performance is much worse than that of masonry structures and reinforced concrete structures. As the temperature rises, the mechanical strength of steel will decline. When the temperature rises to the critical temperature of steel (generally 540°C), its yield stress is only 40% of that at normal temperature. When steel is directly burned by high-temperature flames, it has a fire resistance limit of only 15 minutes. Using fireproof coatings is an ideal method for fire protection of steel structure buildings. The steel structure fireproof coating is applied on the surface of steel members to play a role in fireproof heat insulation protection, prevent the steel from rapidly heating up in a fire and reducing its strength, and avoid the steel structure losing its supporting force and causing the building to collapse.

[0004] Steel structure fireproof coatings can generally be divided into non-expansive and expansive types. Expansive fireproof coatings mainly generate inert gases through reactions when encountering fire to expand and insulate heat. Non-expansive fireproof coatings mainly rely on the heat insulation mechanism of the material itself. However, when expansive fireproof coatings expand when encountering fire, they release a large amount of harmful gases, which not only cause certain pollution to the environment, but also cause varying degrees of physical harm to fire-fighting personnel and on-site evacuation personnel, and in severe cases, even death. Therefore, considering from the aspect of environmental protection, non-expansive fireproof coatings have prominent advantages. However, when non-expansive protective coatings meet the fire resistance limit of 3 hours, most of them require a thickness of 35 - 40 mm. Even though some documents disclose a few non-expansive fireproof coatings with a thickness less than 30 mm, due to reasons such as high cost, they have not gained a firm foothold in the market. Therefore, the comprehensive performance of the thickness and fireproof performance of non-expansive fireproof coatings needs to be further improved. Summary of the Invention

[0005] The purpose of the present invention is to provide an inorganic non-expansive fireproof coating, which is characterized in that, by weight, its components include: 300 - 400 parts of cement, 150 - 250 parts of expanded vermiculite, 150 - 250 parts of expanded perlite, 50 - 150 parts of modified fiber, 100 - 200 parts of slag powder, 2 - 6 parts of cellulose, 8 - 13 parts of redispersible latex powder, 1 - 3 parts of polypropylene fiber, 10 - 30 parts of a fireproof heat insulation and flame retardant with water absorption and expansion properties, and 30 - 50 parts of additives;

[0006] In actual use, the amount of water used satisfies: mass ratio of coating to water = 1:(1.2 - 1.5);

[0007] Among them, the cellulose is carboxymethyl cellulose, carboxyethyl cellulose or carboxypropyl cellulose

[0008] Among them, the additives include polyethylene glycol and water reducing agent;

[0009] Further preferably, it is 350 parts of cement, 200 parts of expanded vermiculite, 200 parts of expanded perlite, 100 parts of modified fiber, 150 parts of slag powder, 4 parts of carboxymethyl cellulose, 10 parts of redispersible latex powder, 2 parts of polypropylene fiber, 20 parts of a fireproof, heat-insulating and flame-retardant agent with water absorption and expansion properties, 24 parts of polyethylene glycol, and 20 parts of water reducing agent; in actual use, 1400 parts of water are added.

[0010] The preparation method of the above non-expanded fireproof coating comprises the following steps:

[0011] (1) Weigh the corresponding amounts of powder materials;

[0012] (2) Place the expanded vermiculite, expanded perlite, modified fiber, and slag powder in a stirring kettle for mixing, and the stirring time is 2 - 4 hours;

[0013] (3) Add the cement to the above stirring kettle and stir for 0.5 - 1.5 hours;

[0014] (4) Then add the remaining powder materials, namely carboxymethyl cellulose, redispersible latex powder, polypropylene fiber, a fireproof, heat-insulating and flame-retardant agent with water absorption and expansion properties, polyethylene glycol, and water reducing agent, to the stirring kettle under stirring conditions, and the stirring time is 1 - 3 hours, and finally a non-expanded fireproof coating is obtained.

[0015] Among them, the fireproof, heat-insulating and flame-retardant agent with water absorption and expansion properties is prepared from the following components:

[0016] Component A: Elastic waterproof emulsion A, carbon source, charring catalyst, foaming agent, titanium dioxide, elastic waterproof emulsion B and appropriate amount of water; Component B: Water retaining agent; wherein, by mass ratio, in Component A, the weight ratio of elastic waterproof emulsion A, carbon source, charring catalyst, foaming agent, titanium dioxide and elastic waterproof emulsion B is (1 - 1.6):(4 - 8):(1 - 3):(1 - 3):(1 - 3):(0.4 - 0.6); the carbon source is pentaerythritol, dipentaerythritol, tripentaerythritol; the charring catalyst is ammonium polyphosphate; the foaming agent is dicyandiamide, ammonium oxalate, urea or hexamethylenetetramine; wherein, emulsion A is vinyl acetate - vinyl tertiary butyl acetate emulsion or vinyl acetate - vinyl propionate emulsion, specifically preferably Wacker EZ3066 emulsion or rovace661 emulsion; emulsion B is VAE emulsion, preferably Emultex FR 797; its preparation method is as follows:

[0017] (1) Add the carbon source, charring catalyst, foaming agent, titanium dioxide into a grinder according to the proportion for grinding and dispersing;

[0018] (2) Add the mixed powder, elastic waterproof emulsion A and water obtained in step (1) into a high - speed mixer for mixing;

[0019] (3) Granulate the mixture obtained in step (2) by screw extrusion granulation or spray drying granulation to obtain a granular flame retardant semi - finished product;

[0020] (4) Place the granular flame retardant semi - finished product obtained in step (3) in a disperser, stir while spraying elastic waterproof emulsion B, and then dry to obtain fire - proof and heat - insulating filler A;

[0021] (5) Blend the fire - proof and heat - insulating filler A obtained in step (4) with granular water retaining agent to obtain the final product, fire - proof, heat - insulating and flame - retardant agent.

[0022] Among them, the time for grinding and dispersing is 1 - 2 hours.

[0023] Among them, in step (2), the high - speed mixer is a high - speed kneader or a high - speed disperser.

[0024] Among them, in step (4), the stirring speed of the disperser is 200 - 600 r / min.

[0025] Among them, in step (4), the time for spraying the elastic emulsion while stirring is 0.5 - 2 hours.

[0026] Among them, the mass ratio of the fire - proof, heat - insulating and flame - retardant agent to the granular water retaining agent in step (5) is (2 - 3):1.

[0027] Among them, the water retaining agent is a polyacrylic acid - based water retaining agent.

[0028] Among them, the degree of polymerization of ammonium polyphosphate is greater than 600 and less than 1000.

[0029] After adopting the above technical solution, the present invention has at least the following beneficial effects:

[0030] (1) The inorganic non - expanding fire - retardant coating of the present invention is different from the conventional inorganic non - expanding fire - retardant coatings. Conventional non - expanding fire - retardant coatings only rely on a large amount of refractory and heat - insulating fillers such as expanded vermiculite and expanded perlite in a relatively thick fire - retardant coating to achieve the fire - prevention function. However, in the traditional fire - retardant coating of the present invention, a fire - proof, heat - insulating and flame - retardant agent with water - absorption and expansion properties is added. When a fire occurs, the water inside the coating continuously volatilizes, absorbing a large amount of heat from the surface of the steel and delaying the rise in the temperature of the steel surface. When the temperature further rises, the flame - retardant agent A composed of a carbon source, a char - forming catalyst, and a foaming agent will be in a flowing state before the carbon - forming reaction. It can flow into the voids generated inside the fire - proof material after the water analysis and form a carbon layer with a certain strength therein, ensuring the integrity of the shape and the overall strength of the fire - proof material. Due to its early fluidity and appropriate dosage, the above - mentioned fire - proof, heat - insulating and flame - retardant agent with water - absorption and expansion properties only expands inside the voids and does not affect the external integrity and strength of the entire fire - retardant coating. The dosage of the flame - retardant agent must be strictly controlled. If it exceeds a certain amount, the carbon layer formed by expansion will exceed the voids, causing the strength of the fire - retardant coating to rapidly decline. Therefore, the overall fire - retardant coating belongs to the non - expanding type. At the high - temperature stage, partial internal expansion occurs, enabling the coating to simultaneously possess the excellent comprehensive properties of both inorganic non - expanding fire - retardant coatings and expanding fire - retardant coatings.

[0031] (2) When the phosphorus - nitrogen - based intumescent flame - retardant is used in combination with other flame - retardants in the formula, due to the small dosage and their sparse dispersion in the fire - retardant coating respectively, the contact reaction of the char - forming agent, the foaming agent, and the dehydration and carbon - forming catalyst is not complete. Therefore, the flame - retardant effect is poor. In this application, the phosphorus - nitrogen - based intumescent flame - retardant is pre - formed into flame - retardant particles through a waterproof elastic emulsion, enabling the three components of the phosphorus - nitrogen - based intumescent flame - retardant to effectively and fully contact and react with a small dosage, resulting in a good flame - retardant effect.

[0032] (3) In this application, the waterproof and elastic vinyl acetate - vinyl acetate copolymer emulsion or vinyl acetate - propylene copolymer emulsion is used as the binder of the flame - retardant particles. Compared with the binding effect of general polymer emulsions, its more important role lies in its certain waterproof property. The continuously connected binding network inside the flame - retardant particles can effectively coat most of the ammonium polyphosphate, effectively delaying the hygroscopic hydrolysis of ammonium polyphosphate.

[0033] (4) The surface of the granular flame - retardant obtained in step (3) is sprayed with an elastic waterproof emulsion B and dried. The purpose is to form an elastic waterproof polymer film on the surface of the flame - retardant, forming a capsule - coating structure, further improving the waterproof property of the flame - retardant and preventing the large amount of water in the water - retaining agent from causing the ammonium polyphosphate to absorb moisture and decompose and become ineffective.

[0034] (5) The waterproof elastic emulsion A and the waterproof elastic emulsion B have better comprehensive elasticity and waterproofness compared to general emulsions. For general emulsions, such as acrylic emulsions, they have good elasticity but poor waterproofness. Polyurethane emulsions and epoxy resin emulsions have good waterproofness but average elasticity, which will significantly limit the carbonization and expansion of the flame retardant and have a greater negative impact on the flame retardant effect.

[0035] The technical solution of the invention will be described in detail below in conjunction with specific embodiments.

[0036] Example 1

[0037] The preparation method of the fireproof, heat-insulating and flame-retardant agent A with water absorption and expansion properties includes the following steps:

[0038] (1) Add the carbon source pentaerythritol, the char-forming catalyst ammonium polyphosphate, the blowing agent dicyandiamide, and titanium dioxide into a grinder according to the mass ratio of 4 kg: 2 kg: 2 kg: 2 kg, and grind and disperse for 1.5 hours.

[0039] (2) Add the mixed powder obtained in step (1), the elastic waterproof emulsion A, and water into a high-speed mixer for mixing; the masses of the elastic waterproof emulsion A and water are 1 kg and 0.5 kg respectively, and the elastic waterproof emulsion A is EZ3066 emulsion. The high-speed mixer is a high-speed kneader.

[0040] (3) Granulate the mixture obtained in step (2) by screw extrusion to obtain a granular flame retardant semi-finished product;

[0041] (4) Place the granular flame retardant semi-finished product obtained in step (3) in a disperser, stir while spraying 0.5 kg of the elastic waterproof emulsion B (Emultex FR 797), and then dry to obtain the fireproof and heat-insulating filler A. The dispersion and stirring speed is 400 r / min.

[0042] (5) Blend the fireproof, heat-insulating and flame-retardant agent obtained in step (4) with the granular polyacrylic acid-based water-retaining agent according to a mass ratio of 2:1 to obtain the final product, the fireproof, heat-insulating and flame-retardant agent A.

[0043] Example 2

[0044] On the basis of Example 1, the amount of water used in step (2) is adjusted to 6 kg, the high-speed mixer is selected as a high-speed disperser, and spray drying granulation is used in step (3), and other preparation steps are the same to obtain the flame retardant B.

[0045] Example 3

[0046] (1) Add pentaerythritol as the carbon source, ammonium polyphosphate as the charring catalyst, dicyandiamide as the blowing agent, and titanium dioxide into a grinder according to the mass ratio of 4 kg: 2 kg: 2 kg: 2 kg, and grind and disperse for 1.5 hours. Then add 5 kg of granular polyacrylic acid-based water retainer for blending. The final product, fireproof, heat-insulating and flame-retardant agent C, is obtained with a mass ratio of 2:1 before and after.

[0047] Example 4

[0048] On the basis of Example 1, omit step (4) to obtain fireproof, heat-insulating and flame-retardant agent D.

[0049] Example 5

[0050] On the basis of Example 1, in step (1), add 8 kg of expandable graphite and 2 kg of titanium dioxide into a grinder for grinding and dispersing for 1.5 hours. The other preparation steps are the same to obtain flame retardant E.

[0051] Example 6

[0052] On the basis of Example 1, replace elastic waterproof emulsion A and elastic waterproof emulsion B in steps (2) and (4) with the commonly used polyurethane waterproof emulsion Dispercoll U53 in the market. The other preparation steps are the same to obtain flame retardant F.

[0053] Example 7

[0054] The raw material components of the inorganic non-expandable fireproof coating are 350 parts of cement, 200 parts of expanded vermiculite, 200 parts of expanded perlite, 100 parts of modified fiber, 150 parts of slag powder, 4 parts of carboxymethyl cellulose, 10 parts of redispersible latex powder, 2 parts of polypropylene fiber, 20 parts of fireproof, heat-insulating and flame-retardant agent with water absorption and expansion properties, 24 parts of polyethylene glycol, and 20 parts of water reducing agent; during actual use, add 1400 parts of water.

[0055] The preparation method of the above non-expandable fireproof coating includes the following steps:

[0056] (1) Weigh the corresponding components of the powder materials;

[0057] (2) Place the expanded vermiculite, expanded perlite, modified fiber, and slag powder in a stirring kettle for mixing, and the stirring time is 3 hours;

[0058] (3) Add the cement into the above stirring kettle and stir for 2 hours;

[0059] (4) Then add the remaining powder materials, namely carboxymethyl cellulose, redispersible latex powder, polypropylene fiber, fireproof, heat-insulating and flame-retardant agent with water absorption and expansion properties, polyethylene glycol, and water reducing agent, into the stirring kettle while stirring. The stirring time is 3 hours to finally obtain the non-expandable fireproof coating.

[0060] Among them, thick inorganic non - expanding fire - retardant coatings A, B, C, D, E, and F are obtained by using fire - retardants A, B, C, D, E, and F with water absorption and expansion properties prepared by Examples 1 - 6.

[0061] During actual use, the above - mentioned fire - retardant coatings are mixed evenly with 1400 parts of water.

[0062] Fire - resistance test

[0063] The fire - resistance limit is tested according to GB14907 - 2018, and the coating thickness is 25 mm.

[0064] Sample type Type of flame retardant Fire resistance limit / min Inorganic non - expanding fire - proof coating A Flame retardant A 230 Inorganic non - expanding fire - proof coating B Flame retardant B 245 Inorganic non - expanding fire - proof coating C Flame retardant C 160 Inorganic non - expanding fire - proof coating D Flame retardant D 200 Inorganic non - expanding fire - proof coating E Flame retardant E 140 Inorganic non - expanding fire - proof coating F Flame retardant F 190

[0065] Thus, it can be seen that the flame - retardant performance of the inorganic non - expanding fire - retardant coating added with the flame - retardant modified by a special process has been greatly improved.

Claims

1. An inorganic non - expanding fire - retardant coating, characterized in that, by weight, its components include: 300 - 400 parts of cement, 150 - 250 parts of expanded vermiculite, 150 - 250 parts of expanded perlite, 50 - 150 parts of modified fiber, 100 - 200 parts of slag powder, 2 - 6 parts of cellulose, 8 - 13 parts of redispersible latex powder, 1 - 3 parts of polypropylene fiber, 10 - 30 parts of a fire - proof, heat - insulating and flame - retardant agent with water - absorption and expansion properties, and 30 - 50 parts of additives; Among them, the fire - proof, heat - insulating and flame - retardant agent with water - absorption and expansion properties is prepared from the following components: Component A: elastic waterproof emulsion A, carbon source, char - forming catalyst, foaming agent, titanium dioxide, elastic waterproof emulsion B and appropriate amount of water; Component B: water - retaining agent; Among them, by mass ratio, in Component A, the weight ratio of elastic waterproof emulsion A, carbon source, char - forming catalyst, foaming agent, titanium dioxide and elastic waterproof emulsion B is (1 - 1.5):(4 - 8):(1 - 3):(1 - 3):(1 - 3):(0.4 - 0.6); The carbon source is pentaerythritol, dipentaerythritol, tripentaerythritol; The char - forming catalyst is ammonium polyphosphate; The foaming agent is dicyandiamide, ammonium oxalate, urea or hexamethylenetetramine; Among them, emulsion A is vinyl acetate - vinyl tertiary butyl acetate emulsion or vinyl acetate - acrylate emulsion; Emulsion B is VAE emulsion; Its preparation method is: (1) Add the carbon source, char - forming catalyst, foaming agent, titanium dioxide into a grinder according to the ratio for grinding and dispersing; (2) Add the mixed powder, elastic waterproof emulsion A and water obtained in step (1) into a high - speed mixer for mixing; (3) Granulate the mixture obtained in step (2) by screw extrusion granulation or spray - drying granulation to obtain granular semi - finished flame - retardant; (4) Place the granular semi - finished flame - retardant obtained in step (3) in a disperser, stir while spraying elastic waterproof emulsion B, and then dry to obtain fire - proof, heat - insulating filler A; (5) Blend the fire - proof, heat - insulating filler A obtained in step (4) with granular water - retaining agent to obtain the final product, the fire - proof, heat - insulating and flame - retardant agent.

2. The fire - retardant coating according to claim 1, characterized in that, in step (1), the time for grinding and dispersing is 1 - 2 hours.

3. The fire - retardant coating according to claim 1, characterized in that, in step (2), the high - speed mixer is a high - speed kneader or a high - speed disperser.

4. The fire - retardant coating according to claim 1, characterized in that, in step (4), the stirring speed of the disperser is 200 - 600 r / min.

5. The fire - retardant coating according to claim 1, characterized in that, in step (4), the time for spraying elastic emulsion while stirring is 0.5 - 2 hours.

6. The fire - retardant coating according to claim 1, characterized in that, in step (5), the mass ratio of the fire - proof, heat - insulating and flame - retardant agent to the granular water - retaining agent is (2 - 3):

1.

7. The fire - retardant coating according to claim 1, characterized in that, the water - retaining agent is a polyacrylic acid - based water - retaining agent.

8. The fire - retardant coating according to claim 1, characterized in that, the polymerization degree of ammonium polyphosphate is greater than 600 and less than 1000.

9. The fire - retardant coating according to claim 1, It is characterized in that the auxiliary agent comprises polyethylene glycol and water reducing agent.

10. The fireproof coating according to claim 1, it is characterized in that the cellulose is carboxymethyl cellulose, carboxyethyl cellulose or carboxypropyl cellulose.